Hi, HM, and welcome!
OK, you've talked about what the alcohol is doing to him--what is it doing to YOU? You are talking about leaving (even though you think you shouldn't), so things must not be so great for you.
For what it's worth, I left my last husband fifteen years ago, after he almost died of liver failure. I did it because it was killing ME to watch him, and I was sure he wouldn't last a year once I left. Well, it's fifteen years later, he's still alive (and still drinking--I'm sure his health isn't great), and I'm a lot happier.
We have a Friends and Family forum where you can talk to a bunch of other people in similar situations--we understand, believe me.