There is a registry of prisoners on the web. If he's still in, he would be there. If he's been released, it should show his first known address. If you're not sure how to find it, as a computer buddy. I found it on the web all by myself (but I'm pretty computer savvy.) If you know the prison he was in, that helps, but if not, just the state will do.
I think I really would make an honest attempt to get ahold of someone in the family. At this point, he may not care about the quilt, but perhaps he has a sibling or children that may care very much! Those are the people you're really doing this for, not really for him.