What is happening to him is what happens to people as their liver starts to fail.
From the information provided it is likely your father has advanced cirrhosis. Since the liver normally filters toxins from the blood when the liver is too damaged to perform all of its functions ammonia, which is formed in the small intestines travel to the brain through the blood stream. The results of ammonia on the brain is called "Hepatic encephalopathy" (HE). Early manifestations of hepatic encephalopathy include episodes of forgetfulness, daytime sleeping with nighttime insomnia, and subtle behavioral changes. Asterixis, a flapping tremor in the hands and wrists is a frequent characteristic.
The good news is there is treatment to manage these symptoms.
The medicines Lactulose and rifaximin.
Your dad should be seeing a hepatologist (liver doctor) at a liver transplant center in your area. These people are the only ones qualified to help your dad at this point. He may need a liver transplant in the future so the sooner he connects up with a transplant center the better.
You say your father has pneumonia? Pneumonia can be fatal for a person with advanced cirrhosis. I assume he is hospitalized? Your dad should be vaccinated against Pneumonia, hepatitis A & B.
There are many things your father needs to do at this point in his illness to help him to be as well as possible, for as long as possible. Make sure he connects up with a transplant center as this could be a life and death issue. Waiting any longer at this point is highly dangerous.
Good luck to the both of you.
Hectorsf
It’s possible his liver is decompensating; this occurs when the organ can no longer filter toxins from the blood. How are they managing this; is he taking Lactulose/rifaximin to help prevent ammonia development? Is he confused or combative?
He will eventually require a liver transplant. Has be been evaluated by a transplant center yet? Who is managing his care; he needs to be seen by a hepatologist who understands his condition.
Sorry to hear your family is going through this. Good luck to you both,
Bill
Sorry you and dad are going through this. All I can offer is that your dad should be seen by a Hepatologist. You can find this type of liver specialist at university teaching hospitals. My prayers go out to you and your family.