Hi complicated1, it sounds like he does want to get sober but when he is, he doesn't think he can do it, or the cravings get the better of him. Now his boss knows about it the decision may be taken out of his hands.
You can't do anything for him; he has to make that decision himself. It doesn't matter one bit what he says, only actions count. Your best course of action is to make sure you aren't enabling or rescuing him because that will make it easier for him to continue drinking.
Try reading the stickies at the top of the F&F forum for your own education. I'm sure many of responders will be along soon to talk about their own experiences. Look after yourself.