There are many symptoms for late stage alcoholism ... including muscle atrophy, especially of the arms and legs. A swollen belly can be a symptom of acsites or fluid retention due to liver disease. My late husband had both of these along with many other symptoms. He also became mentally confused and had serious short term memory problems.
He developed assorted digestive problems as well and he became anemic because of his inability to properly absorb certain vitamins and nutrients. He also developed vision problems related to this problem. Blood tests need to specifically be ordered to look for anemia - as it is not an uncommon problem for alcoholics, but one that is rarely mentioned. This problem can easily be improved with multiple vitamins especially B vitamins. He also developed pneumonia - another symptom of alcohol damage. He developed jaundice after taking Cymbalta for just a few short weeks - it improved after he stopped taking it - but never completely went away. They later put much stronger warnings on this drug regarding alcohol use.
At first my AH thought his weaker, thinner arms and legs ... and what appeared to be weight gain around his stomach - was all due to lack of exercise. Even his doctor missed the signs. His belly continued to enlarge ... and when I noticed his ankles swelling, I knew it had to be something serious. After an ultrasound, it was confirmed to be fluid retention due to liver damage. He was given diuretics that resulted in a loss of over 30 lbs of fluid in a few weeks ... but was told his belly would never completely go away. Once my AH thought he had developed life threatening symptoms, he was actually frightened enough to seek medical help, but unfortunately, it was too late for him. A short while after this diagnoses, he passed away due to a variety of reasons all alcohol related, including cirrhosis.
It seemed almost impossible to believe - but he had been sober and healthy for 2 years prior and then relapsed. After over 25 years of alcohol abuse, and almost no health problems ... when he relapsed, his health deteriorated and declined rapidly. He went from strong, energetic and working long hours ... to sickly, confused and frail in just a few short years.
At this point, in your situation, a loss of some muscle mass and a small belly may not mean anything serious - it could be just getting older or lack of exercise ... or it is possible they are symptoms related to alcohol abuse.
There is a lot of information on the web about late stage alcoholism and related health problems ... and if possible - you may want to recommend he see a doctor ... and make sure the doctor knows his history with alcohol. Of course, realizing with an alcoholic and their never ending denial, it could be a waste of time to even suggest medical help.
By the time my AH finally realized just how sick he really was, despite all the previous warnings and escalating symptoms, for him, it was too late to recover ... too late to make the changes that could have saved his life.