How to approach a business partner about his drinking
Not sure that this is the right place, but kind of shell shocked right now.
I have a partner that I went into business with 2.5 years ago. He is 70 years old. I have noticed that his work has been extremely sloppy over the last few years and mistakes were some that no one in his position should be making. A couple leading to the loss of major clients. I have been concerned that this may be due to some kind mental disorder like Alzheimer's or dementia. A few weeks ago I was discussion one of the big mistakes with one of my managers that has worked with my partner for nearly a decade and asked if he had seen anything like that from my partner before I bought into the practice and he told me that he thought that he was an alcoholic because he caught him taking a drink of vodka from a bottle in his office once. I shook this off as a misunderstanding/overreaction because I will pour a nice bourbon sometimes at the end of the day and I'm done working and just winding down. The biggest surprise to me was that my partner was drinking vodka because we had been to dinner a few times with our spouses and he would only drink one beer and always makes a point to say that he only drinks beer and only has one from time to time when he is out at dinner.
Fast forward to yesterday morning... I walked into his office to ask him something (around 10:00 am) and didn't see him, went back to my office and heard him close a file cabinet in the closet in his office, so I went back into his office. When I walked in he had a mouthful of something that he swallowed before he answered my question. When he went to lunch I went into his file cabinet in office closet and it was filled with vodka bottles (liters and miniatures), a few full a few empty. Since then I have counted his file cabinet opening 6 times yesterday and 11 times so far today.
This is pretty new to me. I drink a lot socially with a bunch of people mainly on the golf course. I feel like I can tell when they catch a buzz or more, but there is nothing that leads me to believe that my partner is drunk from my interactions with him. I have been dreading a conversation of potentially ending our partnership due to his mistakes, but this is the final nail in the coffin. I am not even sure how to approach the drinking thing, because if it is anything like the rest of his mistakes, he will deny it was done, and when shown the facts start blaming someone else or making excuses. At this point my mind is made up that I am ending the working relationship with him, but I worry what it will do to him. He has no worries financially to the point that his kids should never have any worries financially, but his entire identity is his work and he always worries what anyone thinks about him. When I exit the practice I will have a professional responsibility to let clients know why as well as a professional responsibility to our licensing board. My first thought is to talk to his wife or his best friend who I have become pretty close with. I want him to get help if he has a problem, but I can see him saying that I made all of this up because it will look like I benefitted.
Is there any way that I can be overreacting? Are their any other signs that I should be looking for to confirm/ease my suspicions? How should I go about getting him the help he needs if he does have a problem?
Sorry for the long essay, I just have no idea what am I doing.