I have a friend who's like that as well. But what can we
do?
If you're spiritual, then pray.
If you're not, all you can do, is use him as a model. A model of
someone whom you do NOT want to be when you grow up.
I'm doing the same thing, though my dad isn't really that bad, he
has a lot of character flaws that i'm adapting to as i grow up,
growing up to be the exact opposite of him.
I guess that's the only thing we can do. Of course, you could try
talking to him, but i'm not placing any high hopes there. You could
get your grand parents to talk to him as well, to try and whack
some senses into him.
But this is a gray area that i don't quite know as well, maybe can
wait for Yunhaier or someone else who knows to post..