I actually have 4 brothers that all look to me when they want new music. The older one is married and now listens to country, so he's a lost cause.
The younger ones still have hope, though.

The one that just brought back a good spindle of my cds is a college student in the middle of farm country and has roommates that listen to rap. I let him borrow about 15 cds at a time and he'll later go and buy what he liked or look for others like it.
I have a brother that is 14 and I'm just starting to corrupt his mind. He mostly listens to video game music and I'm trying to find some way to get him interested in some other stuff. The younger ones do like that jazz.

Maybe get him into some Four Tet or Tortoise, you don't have to worry about naughty lyrics and its an opening to the indie scene with still a jazzy feel.