I did not experience hepatic encephalopathy during my liver disease and failure. My doctors kept careful watch on my ammonia levels and they always stressed to my husband to be alert for mental signs where I wasn't acting like myself. He was supposed to report it if he saw signs of it.

Here is what I found from The American Liver Foundation.
https://liverfoundation.org/for-patients/about-the-liver/diseases-of-the-liver/hepatic-encephalopathy/diagnosing-hepatic-encephalopathy/

adah, Have you contacted the doctors about his mental changes? Is he still taking lactulose?

@adah it does sound like HE and I presume the doctor must have felt that he did if he put him on lactulose. I never had a biopsy for my cirrhosis diagnosis, I believe I had a CT scan. I remember the test -- I had to drink some horrible liquid in three parts and then have a very brief test done -- but it was so long ago, and I am not a medically inclined person, that I forget which test it was!
From what I have heard people experience HE in many different ways. My HE episodes started with a really upset stomach and fatigue. They progressed to being irrational, sometimes minor, sometimes major. For the minor ones, I could sleep it off. The more major ones put me in a hospital.
I hope if it is his liver you are able to get him to a hepatologist. I live in NH and there is only one in the state, two hours away at Dartmouth, but Boston is only 55 miles away so I went there when it was determined that I had cirrhosis. The hospital at Dartmouth does not do liver transplants either.
JK