Cirrhosis and a fatty liver can go hand in hand. A fatty liver is very common in drinkers and can lead to cirrhosis. This is very typical for alcoholics. That's a long time to be a drinker so there very well could be significant damage already done to his liver from scarring which is cirrhosis.
Everything is going to depend on how much damage has already been done. The liver has the ability to regenerate, but it cannot do that once cirrhosis has occurred. Cirrhosis is permanent damage that does not go away. If the damage is severe, only a transplant will save their life. If caught in the early stages where the damage is not so bad, then if they quit drinking and take care of themselves, they can get well again.
I don't know how much damage has been done to your father's liver, but one thing is for certain. If he does not stop drinking forever, it will lead to total liver failure and death. Getting a transplant will be very difficult for him since they don't give transplants to anyone that is an active drinker. He would have to quit and wait at least 6 months before they will even consider him for a transplant. Liver failure is not an easy way to die. I hope someone in your family can talk some sense into him before it kills him. Good luck.
Had cirrhosis and a liver transplant.