My H smoked pot, too and I am sure he still does and probably more than when he lived here. OW is fine with it or so she said before she started sleeping with my H. (we were friends) H has smoked every day for more than twenty years. I believe it has caused his MLC to be worse than normal. I do know that it has contributed to his memory issues. He tells me I said and did things that I know I didn't ever say or do. Maybe he is hallucinating. Sad because he iwas a bright and loving man.
Everything happens for a reason, maybe Dad needs to find that it isn't better out there, he needs to realize how good he had it here. Maybe he will find God and that is the most important thing when he finds Him he will know he is supposed to come home.