Well I used to be just like him, when I first became psychotic, I reached out to weed and alcohol. Weed made me worse but also high at the same time, so I gave up on it, and alcohol did the trick, it relieved my symptoms and helped me sleep.
If he is your son, cut off his allowance and make him have a curfew. If he’s living in your house, he should obey you, especially if he is a minor.
Alcoholism and schizophrenia tend to get married after a few nights together, so nip his drinking habit in the bud before he gets like I was- a raging alcoholic. They don’t wanna get divorced, either. Quitting alcohol was one of the hardest things I have ever done.
But if he is on meds (Im sorry I dont read your posts very often, the Family section is beyond my realm, I stick to the diagnosed section), he really needs to be a clean monkey, with no drugs or alcohol in his blood. Mixing meds with weed is just cancelling each other out, and alcohol and meds can be dangerous because they decrease your tolerance to alcohol AND meds can be deactivated by complete intoxication.