@shacquie, My first step toward an appointment with liver transplant clinic was thru my local GI (gastroenterologist). He diagnosed my disease, and he monitored/treated me until I needed higher level care. And so, I am happy to read that your mom already has an appointment scheduled with a GI to look at her current health condition.
In my experience, I did not have the episodes of high ammonia or take lactulose, so I have no comment on that. However, each of us will experience different symptoms along the way and it can become very confusing. I did receive a transplant 17 years ago.

Please know that it is 'okay' to call the GI's office to check on an earlier appointment, or to report change in mom's condition.
Sending Hugs and Hope.