How bad is Elon Musk's drug use?

I know there have been some new stories about Tesla board members saying they're concerned about it and he didn't really give a good answer to Don Lemon in that interview. I was just curious as to if there is anymore information on exactly how severe his drug use is.

I've heard he uses Coke, Ketamine, LSD, and mushrooms but I can't seem to find anything really saying how much or how often.