I have dealt with people with alcoholism, including in my own family. At some point you have to quit enabling. People who don't hit bottom very, very rarely get help. I would say never but I'm sure there are a few outliers out there. Just from the narrative of the post they have tried many times to get him help but he refuses. Sometimes tough love is the best you can do for someone. A guy who hasn't moved out of his parent's house in 40 years likely needs a little tough love.
I defended Larry Eustachy back in the day saying that they should have given him a chance at treatment. But later, even Larry himself said it wouldn't have worked. He wasn't ready to give up the bottle. As we say in recovery circles, he hadn't hit bottom.