Hello Faith.
Is your husband attending Al-anon? He needs to go! Making ultimatums you cannot stand by is no way to deal with an addict. Your son is only learning what he can get by with.
You are the only one who knows when you have had enough. When that time comes, do what you have to do. It's understandable that you want to stand with your husband, but he is being unclear about his own position. Clarity is a must.
Keep posting.
Smoke