Can livers heal after severe alcoholism?

Livers can heal. Alcohol adversely effects every organ in the body, except the kidneys. Alcohol can cause liver disease, but if a person quits drinking before much damage occurs, the liver can regenerate itself. The key of course is to quit drinking before it's too late to prevent irreparable damage.
Sometimes. It depends on how severe the liver damage has been, and how committed the alcoholic is to avoiding relapse. If an alcoholic with fatty liver stops drinking, the liver may recover. If things progress to cirrhosis, additional nutritional and other treatments may be needed. If there are ascites, varices, and mental status changes, liver transplant may be needed -- but is very difficult.