I believe, based on the information I have read in many sources, that the alcoholic brain is permanently affected and that some of the damage they do is irreversible. For one, alcoholics tend to have chronic thiamine deficiency, which is a B vitamin, which has been tied to brain health. After-death studies have clearly shown that alcoholism causes shrinking of the brain.
It is sad what people do to themselves and their relationships with others. I watched AXBF go from being the sweetest, most loving man I'd ever met to absolute evil.