First thing I would do is make an effort to secure the house against intruders. Things like:
1. Security doors. This can be a solid core door or a second, metal door that affixes to the outside with one way screws. The point is that to get through it will take some extra effort, provided you didn't open it for them.
2. Peep hole. Use it, and if you don't have one, get one installed. If you aren't expecting company, and you don't know the person on the other side of the door, simply don't open the door.
3. Plant thorny stuff under windows. I don't like the idea of barring windows due to the risk in a fire, but some pretty rose bushes can make getting to the windows a bit tougher.
4. Sliding glass doors. Ugh. I freaking hate these things. If you're in a tropical climate, you probably have 'em. Getting rid of them is probably out, but you should at least keep a bar in the track at night or when you're out. Simple dowel from the hardware store or an old broom stick cut to size will do the trick.
5. Garage door opener. Serves two purposes. One, you can get into your garage without getting out of your car. Two, it makes it harder to force open the garage door.
6. Motion activated external lights. These may or may not work. If you're in a more remote location, they may not deter someone.
7. A fence. Realistically, a standard size fence isn't going to keep anyone out or in. However, it does two things. First, it establishes a boundary. If someone jumps a fence to get at you, it shows some intent on his part. Second, the house without a fence is just a bit easier to get in and out of.
8. Alarm system. You have two options. Option one is to hire an alarm/security service and get hooked up with an alarm system that also alerts the company, who can both call the police on your behalf and send their own patrol. If you're on a budget, you can forgo the service part. If you get motion detectors on your main entrances, and glass break detectors on your windows, you're not looking at too much of an expense. You can hook those up to lights, noise makers, and even cameras. Cameras are great, because in the event of a robbery you can barricade in your bedroom and if the perpetrator leaves, you give the police a better chance of catching them. However, even a basic setup with a loud alarm serves a purpose. The housebreaker may run off if surprised by the sound, and if you're sleeping (and especially if you're a deep sleeper), that sound will wake you up pretty fast, and let you know something is going on. If you have an alarm company do a basic setup, you can get off fairly lightly on the bill and you also get the cool "Protected by..." company sign/sticker to put in your window or on your fence. The bad guy doesn't know whether you have the full service or not. I've also heard of cases where folks can get just the signs from a company, though I'm not sure about the accuracy of that claim. (I could see a liability issue for the alarm company there, so not sure if any would really do it.)
9. A canine companion. It'll cost you more in the long run, but a dog is a heck of a great thing to have around. A large dog may frighten a home invader off, or even subdue one. On the other hand, that dog can be very easily removed with pepper spray or a blunt instrument to the head by someone experienced with dealing with dogs. The most important thing to look for, in my opinion, is a breed that is alert and will let you know someone is there. In other words, an organic alarm system. My father's little terriers did the barking, but he always did the biting. True story: A serial rapist broke into my grandmother's house in Miami a few years back. My parents happened to be visiting and sleeping in the guest room. Their eight pound Yorkie woke them up, and my father ran the guy off. That dog did all of his fighting from the rear echelon, but he was a good little alarm system.
10. I probably left off something, so fill in the blanks here. My point in all of these is that they're relatively inexpensive things you can do which will give you two forms of protection. One, they will hopefully make criminals skip over your house when looking for a target. Two, they will lend some weight to your legal defense if you are forced to use a firearm to defend yourself. You made an effort to secure your property, and the criminal made a bigger effort to subvert your security measures.
That said, I have a few opinions on firearm selection, though a few of these will be repeats from prior posts. I'm going to spew them all out anyway because I'm on my lunch break and I'm feeling talkative. Or type-ative, perhaps? Anyway, here are some criteria/observations I've made, regarding home defense firearms.*
1. It should fit the shooter's hand. There is a nice article here, regarding
handgun fitting. I just found that site last week, and I think it's a good resource for newer firearms owners. I suggest the OP point his father at it.
2. Caliber selection: Not less than .380 ACP for an auto, not less than .38 SPL for a revolver, unless a medical condition dictates otherwise. Whatever caliber it is, it should be something the shooter is comfortable with, because otherwise they will be reluctant to practice or even to break in the gun properly. Cost of ammo may be an issue as well. In that regard, 9mm is a good choice because it's the least expensive centerfire handgun caliber.
3. Stopping power and knockdown power don't exist. People stop fighting for a huge number of reasons, most of which the shooter has NO control over. Unless you make a fairly difficult CNS hit off the bat, the person isn't going to be forced to break off attacking by the wounds inflicted until their brain runs out of blood. Barring a solid CNS hit, handguns don't stop people. People stop themselves after getting shot. Your main concern is getting a weapon you can shoot straight under stress and getting a caliber that gives good penetration.
4. Auto versus Revolver. I hear people say that a revolver is easier to use than an automatic. Autos are more complicated machines, harder to clear, less reliable, etc. This is somewhat true and somewhat off at the same time. A well made revolver is very reliable. The Taurus stainless snubby .357 I had a few years back was not. (I'm not singling out Taurus, but they do have a bit of a rep for turning out revolvers that have weak mainsprings and that are prone to cylinder binding. I happened to get one of those.) So, quality counts. A good Smith and Wesson or Ruger revolver are going to generally be a solid bet though. Both can be had a great prices used. There are still a ton of retired police S&W revolvers floating around.
The second issue on revolvers is shooting accurately. It takes a LOT more training and practice to develop a good double action trigger pull than it does a single action pull. Even autos with a DA/SA have an edge on the follow up shots. and Glock or similar (Springfield XD, S&W M&P autos for example) trigger setups are easier on all shots.
Autos are also a little easier to hit with (more pointable) and more controllable in recoil than a revolver due to lower bore axis.
5. Get training and get practice. There's no excuse not to get trained both in the mechanical aspects and the legal aspects of use. You won't be proficient, especially under stress, if you don't get trained and get in some practice time.
6. If you don't have a gun in your hand, you're not going to get much of a chance to use it. This argues against the long gun, whether shotgun or carbine, for home defense. I'm not saying both aren't superior in a fight. What I'm saying is that in a home invasion, you will either be taken while you answer the door, on your way to the door from your vehicle (or way out) or at any random time someone breeches your door or window to enter your home. Someone could come through my sliding window (hate those) or my front door as I sit typing this. I'll have to fight them off with my can of Pledge or an ink pen, though.
If you have only ONE gun in the home, I think it's a good idea that it's one you'll have with you at all times. Most people aren't going to drag a shotgun from room to room throughout the day. It's also a lot more discrete to answer the door with a small handgun in your pocket (concealed hammer revolvers excel here) than a shotgun in hand.**
Anyway, my suggestion for the OP would be a small or medium frame revolver from Smith and Wesson or Ruger. This is mainly because his father has at least some prior experience with revolvers. It's also easier to fit a revolver by changing out the grips. I'd suggest three inch or smaller barrel if he's going to be carrying it concealed or in the car, and if it's legal where he lives to do so.
The shorter barrel really is not an impediment to accurate shooting at close range if the gun fits the hand. A longer sight radius means that errors in sight alignment are somewhat mitigated. However, if the shot has to come fast at very short range, just getting the front sight on target is good enough if aiming center mass. If the gun fits the hand, just extending the gun hand towards the attacker gets you halfway home on aiming it.
Also a shorter barrel is more manageable in a grapple situation and a little harder for someone to grab in a disarm attempt.
A nice J-frame S&W .22LR might be a good companion piece to a J-frame .38spl or .357mag. for cheap practice. The main issue IMO on practicing with a DA revolver is getting that DA trigger under control, which can be done with the .22LR.
Another thing you should look at is getting snap caps to practice dry firing.
If your father decides to look at automatics, there are a few which have good reputations.
The
Bersa .380 Thunder has already been mentioned. I do not have first hand experience with these, but they have developed a really good reputation for reliability. Bersa has a non-PP clone in 9mm, .40 S&W and .45 ACP, and those are also spoken highly of. They're about the same dimensions height and length as the 380s, but a bit thicker.
Stoeger now makes the
Cougar, which used to be a Beretta. (Beretta is now making the polymer framed PX4 Storm pistols with a similar design.) These are made on the same equipment as the Berettas, but in the Turkish Stoeger plant. (Beretta owns Stoeger.) From all reports the are as reliable as the originals. They have better ergonomics than some of the thicker gripped and longer trigger pull double stack autos and come in 9mm and .40 S&W. They're service sized sidearms, but they're on the small side of that, so should be a decent size. They have softer recoil than some other pistols in the same calibers due to their rotary barrel setup, which may be a plus for older shooters.
*Just remember, my opinion is worth every penny you paid for it! I'm not a lawyer or a gunfighter, so don't take anything said here as legal advice.
**If you DO pocket carry, I suggest getting a pocket holster, even at home. I've heard more than one story of someone getting other stuff in their pocket into the trigger guard and causing a ND because of it.
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