The liver has great regenerative powers--to a point. My second husband almost died of liver failure but months later was found to have EARLY cirrhosis, and if he quit drinking he would be fine. He didn't stop, and I'm not sure how he's still alive, but he is, and it's been almost 20 years.
Certainly her continued drinking will shorten her life, but it's hard to say what might happen if she quits. She might recover completely.
You might want to consult an attorney about a guardianship if she is incompetent to take care of herself.
Hugs,