Alcoholics will hit their bottom when they are ready. It doesn't really matter where they are. So far as asking your MIL to kick him out, that's really not your call. You can only control what you do in this situation, not what she does or what he does or anything else.
Do you attend al-anon meetings? They can be a valuable source of support and can teach you how to detach from whatever your husband or even your MIL chooses to do.