Welcome to SR
Your not alone. There are many here who understand and from some of what you say...maybe his family understands a little as well.
You are taking in a lot of info at this time. Some of it may be true and some not.
Don't be so hard on yourself. In what you have written, I see a lot of recovery tools have been used by you.
If you are wanting to help him, the best way I know how would be Al Anon meetings. At such meetings you will gather in more tools or refine the tools that you already have..boundaries and holding to them.
You did good. He is where he needs to be...seeking his own answers in a recovery setting.
You are not so much the enabler you may think you are. Be nice to yourself and know you are among friends here.