It's the lesser of two evils. I am not an addict, but have a son who is taking Suboxone. Addicts, unfortunately, lie. That is part of their problem. Lying to themselves and others. My son is supposed to take 1 tablet 2x a day. He takes 3.5 tabs a day. So, he is lying to himself when he says "he's getting better". No matter what you say or do, it's up to the individual to change. Just stay strong yourself and go to NA meetings for support. The best to both of you.
Some doctors believe that sub is a life long med like insulin or something but many think you should be able to get off it is really hard to get off when you have been on a long time as the withdrawals are hard...he would need to taper down very slowly to avoid getting sick. He needs to speak with his doctor about it but really it is a personal choice in many ways.