Sorry to hear that. If you don't mind me asking, out of curiosity, how old was he, what was his prior experiences with drugs and alcohol, and did he have any family history of schizophrenia or similar?

Mental problems like schizophrenia often develop during the ages people start experimenting with drugs (18-25), and while these things can certainly be catalysts, I think the science is still out as to whether such a person would have just developed the disease later on even without the bad trip.