What should I do?

So my STBX smokes pot, which is not a bad thing, imo. But we live in Texas and share a child. He is unemployed and struggles with a handful of mental health problems but also weaponizes them. He's slowly becoming a better person but like a snail. I've had several people tell me that I should just have full custody instead joint custody, but I for some reason feel guilty about that idea. My ex wants to be a good dad and involved, unlike my dad was.