My advise is to tell him you pray he makes the right choices, and step back and let him take charge of his own recovery, or not. Only he can do what is right or not. Those decisions have to come from within himself. Have you and or your mom thought about going to Alanon for support for yourselves?
He is a grown man and will have to decide what he is going to do. He will also have to suffer the consequences or the benefits of those choices.
Let Go and Let God. You cannot control his actions, but you can control your reactions.