You don't have to get him kicked out, but you do have to do something.
Although I don't have any statistics for this, based on what I've heard and read, functioning alcoholics will in the majority of cases straight up refuse to admit they have a problem unless and until something dramatic and life-changing happens to them. This guy's already lost his friends and family so the only thing left is his job, and as long as he can say "I still have a job and still get paid to do what I do", he'll think everything is at least OK.

What's the disciplinary structure where you work? You need to get him hauled up before a disciplinary hearing, organised not by upper management but by his immediate boss and his colleagues, with the message "We know you're capable of great things and there are people out there willing and qualified to help you get back on track to that level of performance again, but you have to stop drinking, altogether, and as soon as possible. If you don't make a firm commitment to laying off the booze and follow it through, we won't hesitate to have you fired, because ultimately you're a liability for the team in your present state." You'll still come across as his friends but he should understand this is an ultimatum.
( .Yeti. El amor en los tiempos del cólera, Fri 10 May 2013, 11:33, Reply)