Oh @REP22 I am so sorry you are going through this. I am very, very familiar with escaping the agonies of dealing with a difficult mother through drink - I spent many years in the “cockroach cafe” (with which I think you’re also familiar? For everyone else, it’s an excellent support thread on here for those dealing with elderly parents).
I think it’s impossible to give helpful advice because I know how painful it all is, but here’s my best shot ..
First, if you drink, you are only punishing yourself, no one else - don’t do it.
Second, boundaries are your friend. Be really clear about what you will and won’t do, and stick with them. You are both adults now, and (assuming your mother still has capacity) she can make her own choices (as can you), but choices have consequences.
But I know that the guilt is so hard, and (at least in my case) my sense of identity is so bound up in what she reflected back to me that boundaries are almost impossible.
Perhaps the best advice is to accept that this is painful, and there isn’t enough alcohol in the world that will make that pain go away.
After mum died, I finally sorted myself out with a therapist (although now we mainly talk about how my learned behaviour with mum plays itself out with my cancer diagnosis 🤣). Is that an option for you?
If not, there are some good self help books out there that might be helpful? I’m currently reading “Are you mad at me?” by Meg Josephson which is really good on the “fawn” response. “Let them” by Mel Robins has mixed feedback but might be worth checking out?
I’m sorry you’re going through this - you are such a wonderful support on here, so lean into us when you need to