Don’t beat yourself up, you can’t blame yourself for other people’s addiction. Your brother in law was already abusing 1 substance (that you knew of), odds are he was probably gonna do all that stuff anyways whether you smoked him out or not.

I think the the most important thing about all this is to not let anything in your life to control you to the point where it affects your happiness.

I don’t know if you really have to quit but if your wife doesn’t like it, then that’d be good enough for me. Unless she tries it and likes it lol.