Yes, those symptoms you mentioned are all withdrawal symptoms, does he have extreme sweating ever?
"End stage" doesn't mean he is at death's door, it just means his alcoholism is severe. It comes, generally, with a lot of health challenges.
He may be fit (although from your descriptions it doesn't' sound like it) and may go to work 50 hours a week, but he can still have alcoholism at end-stage. Look at all the health challenges he is having. He can still function with all of that until he can't.
That's why when some people describe an alcoholic as "high functioning" it is just a misnomer, they are high functioning until they aren't.
My Father was an alcoholic and worked long, hard hours all his life in tough areas of the world, until he retired.