Your boundary is not being around him when he is drinking. Sounds good.
Another conversation with him about it will not get you anywhere. He is not going to do anything different. IME it is simply not possible to have a constructive conversation with an alcoholic about their drinking. It just won't happen and having it a thousand times with slightly different angles doesn't change that. Stop talking, start doing. What can you do to protect that boundary? There are quite a few ways to address that but talking to him or depending on him to follow through on some course of action himself are not among them.