I'm an RN, but I really can't add much to what's already been said here about alcohol and its effects on the liver. It's all been pretty well covered here.
I also lost my only brother a little over 10 years ago, and his death was at least partially due to the fact that he was an extremely high-functioning alcoholic.
While your co-worker might be "somebody's baby," your concerns about his well-being really should be reported to your superiors. If he has already made some mistakes on the job, possibly due to his being drunk on the job, you bear a heavy burden, but one that cannot be ignored. I hate to sound harsh, but if you keep quiet and then someone is injured or otherwise badly affected by his actions, it's gonna be a hell of a thing living with the knowledge that you could have prevented it

.
You could also be doing him a very big favor...perhaps he's diabetic and doesn't realize it. Or perhaps being faced with some kind of intervention might finally make him admit that he has a problem, and he'll do something to change it.
Just present it to your superiors in a way that makes it clear that you're concerned about this man's well-being and the well-being of everyone around you...make sure they understand that you're not doing it to be mean, petty, vindictive, or any other assorted negative emotion. It's clear to me that you're concerned for all the right reasons, and there's nothing wrong with that.