The word "hepatitis" means inflammation of the liver. There are many different types of hepatitis such as the viral kind of A, B, C, and D. There are treatments for them, but hep C is with you for the rest of your life. Other forms of hepatitis can be autoimmune, biliary disease, alcoholic, and fatty liver called NASH. There are more, but these are the most common ones. A simple bloodtest will determine whether or not your father has any viral hepatitis.
There is a lot of things that must happen in order to qualify for a transplant. Passing an evaluation consisting of many medical tests, consult with a psychiatrist, and talking with a social worker is the first step in trying to qualify for a transplant. After doing all that, your case goes before a Board of doctors that will determine if you would be a good candidate for the surgery. If yes, then you will be put on a national waiting list to be called when it's your turn. The sickest get the organs first. A MELD score is what determines how sick you are which goes up to 40 with 40 being the worst. I received my transplant when my MELD was 15.
Compatible blood type and body size are the two factors that the donor and organ recipient must have in common. Before you start to worry about needing a transplant which is a last resort, your father needs to find out more about the condition of his liver and what his options are for getting well. If he doesn't even know whether or not he has any viral hepatitis, then he needs to really talk to his doctor and insist he find out what is going on. A biopsy is the best test to really know what is happening with his liver. Before they do that though, they usually get a CT scan and/or ultrasound. All these tests are done when someone is being evaluated for a transplant along with a number of other ones. Good luck to your father and tell him to get some answers from his doctor. Just telling him he is losing weight from his liver being sick is so vague let alone evasive. It just wouldn't cut it with me. And you don't say anything about what the doctor told him he could do about the problem. Your father is not a 5 year old that wouldn't understand, so the doctor is not doing his/her job if what you say is true. Go to another doctor if this one can't help your father. With liver problems, he should be seeing a gastroenterologist, but the top gun for liver problems is a hepatologist. Many primary care doctors do not know much about liver disease.
I had cirrhosis and a liver transplant plus I'm a nurse.