Friend with problems?

I have a friend who drinks a lot. He drinks to do almost anything, before he goes to school he drinks sometimes, and to go to a movie he takes a flask with him to drink. Whenever he goes to do anything he drinks, he also has an obsession with looking up the effects of drugs. He even ate a ton of Nutmeg simply because he heard it caused hallucinations. What should I do, he has an obsession with doing anything to change his mental state. Any ideas as to why he is so dependant on these drugs to get by?