Right, my goal with asking about "functioning alcoholics" and how extreme he seems wasn't to make myself feel better that he isn't so bad, it's more "Holy crap, he's so bad I'm not sure how he's still alive." That's not just because of the alcohol though, it's also that he just doesn't care, I believe. It's like he's content to live out the rest of his days in a haze to numb the loneliness, depression, etc.
The unwillingness to care for himself is very difficult for my Mom and myself, in that there's guilt no matter whether we choose to help him or not. I keep trying to remind myself that he's a grown man who's perfectly capable while sober. But, were he to die tomorrow from malnutrition, it'd be hard to avoid the guilt of "if I had just taken him some food..." If I took him food tomorrow the disease would kill him some other way though; I can't be a life support system for someone who doesn't really want to live.
As his son, I wish there was something I could do to help, although realizing it's not my responsibility to. I've usually tried to be positive with him, but I may also try being more blunt with him in an attempt to make him see how bad he has become. I've been somewhat blunt with him. But, for example, I've avoided letting him know that he has wet his pants while sitting drunk in front of me, because I've been afraid the extra embarrassment might just make things worse, but maybe it would help.
Anyways, thanks for the thoughts and advice.