Mamabear, welcome to the forum. Unfortunately, it sounds like your MIL is in an advanced stage of liver failure. Cirrhosis is not curable. As you have mentioned, the high ammonia level will make her very confused and "out of it." They may have to increase the Lactulose. I suggest that you read the info in the folder entitled Hepatitis Resources, at the top of the forum page. There is a lot of good information in there on liver disease and it's signs and symptoms, including encephalopathy (from high ammonia in the brain.)
I also have cirrhosis and hep C. However, I've never had encephalopathy or esophageal varices, which can also cause one to vomit blood and is potentially life-threatening. Since she hasn't been sober for 6 mos., she would not be a candidate for a liver transplant, even if they stabilize her. It's really impossible to say how long she has left, as it depends on many factors. Some people last a lot longer than originally predicted, while others go faster. That question is also addressed in the Hepatitis Resources folder. It's also more of a challenge when a liver patient has diabetes.