A,
I am so sorry. I slept in my car a half a dozen times because axh was drunk and wouldn't stop. This brings back horrible memories for me. I am out of that situation and you are on the right path, also. When he was drunk, you didn't engage, you left and sought help. You will have the "honeymoon" period now, he did "bad" and will suck up to you and he will kiss you a$$ for a few days and then repeat.
I hate to say, MIL telling him off while he is drunk only does so much, he probably doesn't remember. You might recommend alanon to MIL also, sounds like she could use some guidance also.
Sending hugs to you, you are on the right path to get out!! Hang in there!!