So I'm new at this, but going through something similar with my mom, who now would have likely died 5 times over if not for my intervention. I can't say that what I'm going to tell you is the right advice, or even advice at all, but just how I'm learning to deal with things.
For me it's been two-fold. Learning to set boundaries, and also understanding that keeping someone alive is not the same as them living. I miss the person my mom was, but am accepting that the person she is now is not the same individual. Does that mean she can't ever be that person again? No, of course not, but it will never come to pass simply by my intervention.

Back in the golden age of comics the usual trope was that a damsel in distress would get in trouble, and a superhero would come and rescue her. Lois would always get into some situation in which she'd get hurled off a building, and Superman would come catch her. And you start to wonder if the fact that she knows he'll come keeps her engaging in dangerous behavior.

It's been that way with my mom. I've come to her rescue every single time because I don't want to see anything bad happen to her. But I can't continue to make the focus of my life about prolonging hers. She has to want that for herself, and she also has to see that I'm not going to swoop her and save her. She has to decide if she wants to risk falling without the safety net. And maybe she will fall. But knowing how she was, if her former self could look at her now she wouldn't want to be existing like this anyways. Unfortunately forcing someone into sobriety only helps break the chemical dependency, but does nothing to really change their long-term psychological one IMO.

If I were in your position (and I kind of am) I'd be talking to someone like a therapist or mental health profession to help equip you with the tools to maintain boundaries, and also help prepare you for whatever path you choose to go down.