When patients develop advanced or "end stage" liver disease, this is called cirrhosis, which is irreversible. The liver is only functioning to a minimal degree. One of the indications that the liver is failing is acumulation of fluid inside the belly, this is called "ascites". There are other problems associated with cirrhosis (confusion which is called "encephalopathy", esophageal varices
which are blood vessels in the esophagus
that can burst and bleed out, liver cancer
Liver transplant is definitely a good option. The survival after a liver transplant is about 85-90% at 5 years after liver transplantation
and depends on the experience of the center, the reason why he is getting transplant (hepatitis C
patients do slightly worse than the rest), the quality of the care post-transplant. To qualify for a transplant the doctors will calculate a score based on some of his labs, which is called the "MELD" score (a high score above >15 is really bad, and a low score is good
By the way the cost of a liver transplant varies from country/city. In the USA it is very expensive, probably around 300000$ or more.