There is a blood test that can be an indicator of possible liver cancer (HCC heptocellular carcinoma) this test is called AFP alpha fetoprotine which if elevated can be an sign of HCC but this would need to be confirmed with an abdominal ultrasound or other medical imaging.
Sorry to say your dad has ESLD (end stage liver disease) with very advanced liver cirrhosis called decompensated cirrhosis meaning his liver is in some stage of failure.
If he wants to survive eventually his only option will be a liver transplant which he won’t qualify for until he has at least 6 months of abstinence from drinking any alcohol.
How long he has until he has a life threatening event like an esophageal varicies bleed.
Infections are another serious complication of ascites. In patients with ascites related to portal hypertension, bacteria from the gut may spontaneously invade the peritoneal fluid (ascites) and cause an infection. This is called spontaneous bacterial peritonitis or SBP. This can also be life threatening.
Hepatic encephalopathy is a decline in brain function that occurs as a result of severe liver disease. In this condition, the liver cannot adequately remove toxins from the blood. This causes a buildup of toxins in the bloodstream, which can lead to brain damage.
Hepatic encephalopathy can be acute (short-term) or chronic (long-term). In some cases, a person with hepatic encephalopathy may become unresponsive and slip into a coma.
Depending on how badly damaged his liver is he may still be able to avoid a transplant but he must stop drinking. That would be best determined by his doctor.
If he wants help he needs to see a hepatologist associated with a liver transplant center. They are best equipped to monitor and guide the treatment of someone with advanced liver disease.
Has he ever had an upper endoscopy to check for esophageal varicies? Did his ascities require draining or are his ascities well controled with diuretics? Do you have any idea what is MELD score is? The MELD score is derived from some of his blood tests and is an estimate of 3 month survival rates. The MELD score (Model for End-Stage Liver Disease) is also used to rank patients by severity of need for the liver transplant list.
Sorry to say but bottom line if he wants to live either with a transplant or have any hope of recovery he absolutely must stop drinking alcohol and any drugs if applicable.
You should try to be allowed to speak with his specialist to better understand his medical situation.
Best wishes to you both.