I'll recommend the first book shown here for a light humoured though quite accurate look at how the English behave.
http://www.amazon.com/s/ref=nb_ss_g...alias=aps&field-keywords=watching+the+english
It can depend were your friend is thinking of spending his time and also how old is he. For example I've observed that amongst young educated men in their early twenties who are mates a friendly hug on meeting seems to becoming more acceptable, though only in large urban areas. That never used to happen except maybe on the sports field and I'm happy to say it doesnt seem to of taken on in the more rural market/farming towns.
As Circle says, the English like their personal space and a normal conversational distance at work would be at least a couple of feet.
We can be slow to open up to people. Were not being unfriendly, just guarded, and it can take an age for us to warm to someone. Hence the formality of our greetings with people.
And your mate is going to have to learn how to use sarcasm. Were probably the most sarcastic, and cynical, race of people in the world. Oh and some self-depreciating humour may help.
He's going to have to learn how to drink. 99% of socialising in this country is done in some sort of pub and inviting any new workmates for a beer or two after work would probably be a good way to break some ice. Though don't overdo it with the beer when with workmates as that can be frowned up on. Alot of my foreign mates think British women are the funniest and friendliess girls on the planet. Personally I don't but if your mates a friendly guy who can talk and have a laugh he'll get on fine with them.
He'll have to get used to people. Everywhere. Theres over 60million of us on an island of ?91,003 square miles. If he wants space theres only a couple of corners of this island he'll find it. I think this is why the English are not the polite people others like to think we are. Were feeling crowded in, and walking through a city centre on a Saturday afternoon can be torture.
Oh and when the English aren't in a pub there shopping. We'll buy and sell anything. Alot of our supermarkets are open 24hours a day and if the other shops could entice us out some drinking den or other then they'd open that long as well.
Anyway just a little bit but I hope it helps.
D.