He can drink all he wants and still have a great career as a coach. He just needs to learn to take a damn cab.
Part of being a serious drinker is knowing ahead of time when you're going to be drinking (and let's face it, you always know) and making transportation plans that don't involve driving yourself. It's entirely a mental thing. If you decide ahead of time that you're going to cab home, then you cheerfully take the cab home, no problem. What gets you in trouble is not making that decision beforehand, and then you start thinking, "I'm fine, I'm fine, it would be a pain in the ass to have to get up in the morning and come all the way back down here to get my car," and then the next thing you know your face is on ESPN.com and your career is on the rocks because you didn't spend a lousy twenty bucks on a cab ride. If you can't handle that planning process, then you can't handle alcohol.