Well, I actually live with my oldest brother, of whom turned 37 this past June. So I was literally in your shoes no more than a few months ago.

Sayin' that, the best advice I can give you is to either find out what his passion is (my brother's a musician in his spare time, so I laid down some bucks to help buy him a new Triton) or do something that both of you can do, like take him to the movies.

Trust me, at that age it's usually the thought that counts.