Then continue to support him. In the meantime, you may want to attend Naranon meetings, and read Codependent No More.
He is an addict, and will be one, regardless if he is clean or not, for the rest of his life. There is no cure for this disease. If you want to dedicate your sanity and peace to an addict and their lifestyle that certainly is your choice.
Welcome, and, I hope this all works out like you would like it to.