I'm probably going to take a little flak for this, but I think you need to think seriously first before bringing this up to the family. I completely agree that he is a horrible human being and he has no excuse for his behavior and that it SHOULD stop. But here's the thing, he's never going to change unless he WANTS to change, which from your post, I don't really see. It seems as though he has no remorse for any of his actions whatsoever. I also worry that if you confront family members with his behavior, they might get defensive (especially his parents and your grandmother). This could result in your being alienated from your family. I think you need to first talk to people who have similar feelings with you about this guy, get a feeling for what sort of reaction the whole family will have. Perhaps have one of these sympathics go with you when you talk to others who will be less understanding. Try not to take your anger at him out on others. Perhaps you can work, as peacefully as possible, to getting everyone on the same page and then move on to getting people to stop enabling him or speaking to him.

This is going to be a slow, uphill battle. You have to keep in mind that no one can control anothers actions, everyone makes their own decisions. I would ALMOST recommend removing yourself from the situation as much as possible, simply because I don't want to see this do more harm to you than good.