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?