Thanks, people. Jason...good for you, brother.
M10...the chemo I had wasn't painful, but it did leave me drained and without much motivation to do anything besides sleep and rest. Each person's dosages/meds are different, though, based on what he/she is facing, and how advanced it is. Chemotherapy just means chemical therapy. There are lots of different chemicals used, and most times a person's regimen is a combination of toxic chemicals which do different things in the body.
Tell your pops-in-law it shouldn't hurt, but that he should be prepared to be bored, lonely, and a little bit frustrated. Books, DVD's, good music and anything else he enjoys would be good gifts. If he's a writer, get him a good journal. If he's gonna have hours of chemo, an ipod or maybe a laptop or little dvd player will help him to pass the time while he's getting the meds.