Help!

I have a 25 yr. old son living at home that spends all day in bed , goes out for a few minutes at night to get cigarettes and coke comes home watches TV all night and then back to sleep. What do I do I have tried everything? I myself is getting VERY depressed watching him kill himself. He also eats lots of Ice Cream which is a diary product and caffene that's in the coke.

Thank to anyone that can help me.
signed Help from Ariz.