Its amazing how we so easily convince ourselves that we are helping, and making things easier, when in actuality we are just getting in the way of them suffering for the consequences of their own actions.
Should have, could have, would have, is not going to get anyone anywhere. You know as well as he does that if he had taken care of things, none of this would have happened, in so many ways. Trying to make him see that is useless, like you said. He sees it the way he wants to see it, and that is using you as a scapegoat for his ****ups. Him acting like a baby about the whole thing, and not assuming any responsibility is typical of an A.
I wouldn't be surprised if he uses the whole thing as an excuse to start drinking again, all the while blaming it all on you.
You did the best you could in the situation. Please don't beat yourself up for it!