I'm very sorry to hear that.  My brother passed away in his 20s as well.  I know he didn't treat himself the way he should have, but having an incurable disease can also lead to depression and self-destructive behaviors.  I see the same thing with my son and can only do my best to help him as much as possible.  I am afraid of what's going to happen when he turns 18 and I can't influence or control him as much.