Take a couple of deep breaths. Now what exactly do you think telling his mom will do? Do you think he will listen to her over you? No. All it will do is involve her in a situation that she can't control either. He has told you he doesn't want help. Without 100% determination from him, there is no hope. You cannot control it. His life is 100% out of your hands. Your options are to sit back and watch it happen before your eyes or leave. Occasionally losing a family is a slap in the face and may encourage him to seek help. Leaving him to fall flat may be his best chance. You do not need to simply watch it happen. Get yourself out of that environment. It is toxic to you and to your son. Follow through on the divorce. Good luck and remember this forum is here. Al-anon is near you and you are not alone.