I don't have a lot to back up my assertions, but I don't have any nice things to say about pot, I would buy into the idea that it can add to someone's poor behavior. I have known a few people to convert their drinking habit into a potsmoking one, and there was some degree of justification for it ("at least pot doesn't do awful things to your body," blah blah). If pot can make some people paranoid (as opposed to "chill" or giddy), why would it not make people irascible? Some scientists are of the opinion that it worsens mental illness (or "triggers" what had not been identified as a problem in the patient before they had pot).
It sounds like you are asking if he will reach a point where he is desperate to change and stop. I don't picture that, but that is because I am not accustomed to hearing about it. It's also possible that he would switch to another drug or return to drinking (who knows), and then things could get worse.
Do you have a way to get counselling and take steps to changing the situation?