Is this a problem? Seeking Guidance

Hi, I'm going to try and explain why I joined, and why I'm not totally sure about the problem I have at home.

I'm Senior at the University of Oklahoma in the States, and I live with my father for financial support, though I find myself living at home less and less. I'm fully mobile, and have been given a great deal of freedom to accomplish the tasks of my academic career and the extra-curricular activites I'm taking on. This is due in no small part to my father, who I would describe as very supportive and accepting of me. 

In fact, part of my confusion comes from how my father acts despite his increasing desire to drink. He works 50+ hours a week, and manages a business run by my family they have owned for decades. They do quite well, and he has a positive reputation in our community for being fair and dedicated to his customers, whom he works with directly since his operation is fairly small, (only 8 employees approximately.) He is a handyman at heart, always learning how to take things apart and put them together again. He's a gear-head, really understands automobiles of many varieties, and thats his line of work. He is teaching himself how to work on computer hardware now, and other electronics like t.v's and radios. He is the most patient and even-tempered person I know, and has not raised his voice to me or anyone else in my presence for months or maybe years. He is never physically violent.

His drinking is heavy however, and daily. Sometimes he is inebriated by the time he gets home from work, but if not it will be one of the first things he does when he arrives. He sneaks around me to drink, though he knows that I know. He has been through formal treatment twice in my lifetime, and over the winter holiday of 2013, he spent a week in the hospital for depression with suicidal intesions...

He came home, and seemed to have recognized that drinking was an issue, but the combined stress of new medical bills and problems at the shop where he works resulting from his absense drove him back to it again. Its been quietly continuing for more than a year now, but it hasn't caused him to stop working, not one day. He keeps up the house, though he often forgets to buy groceries. I'm a vegetarian, and have been trying to improve my diet, but he won't eat what I cook, choosing frozen or box dinners instead of fresh food I always make plenty of for two or even three people. He often takes care of all the household chores and things and NEVER asks for my help. The other day, while installing lights in the garage, he dropped a fixture on himself and gashed his head. It wasn't hospital serious, but I didn't even hear about it until the next day since i wasn't home at the time. He will do any task by himself even if he knows it would be far simpler just to ask for help. I offer constantly, and helped him finish hanging those fixtures yesterday, but I doubt he will learn his lesson from this experience.

My general observation, he doesn't want to rely on anyone else for anything. He wants be self-sufficient, and tries to the point of fault to do so. I'm worried because he may be drinking and driving, and though I offer to take him places, i'm just not around enough to monitor that behavior anymore, and when I am he can disappear without warning. He has never had issues with the law, which better than I can say for myself. I don't know how I can confront him about this drinking that seems totally unmoderated, yet doesn't seem to cause him nearly as much strife as it does me. He take mood stabilizing medication now, a result of his hospital visit. The kinds of medication are dangerous to mix with alcohol, and sometimes he doesn't take them after drinking, but I can't be sure of that all the time.

I'll try and wrap this up with this section, I've had a lot to process and this is the first time i've tried to unpack the experience so its all just sort of...flooding out. But that's why we post right? To vent, decompress, and share whats going on. Well, now the facts are that we are doing alright financially, his shop is doing better. I'm nearly graduated which means no more school costs. We've been talking more, and I try to be home to look out for him. But things beneath the surface disturb me. I have two younger siblings who live with their mother (second marriage ended in divorce, as did the first with my mother), and they have stopped coming to visit on the weekends because of his drinking. He drinks more on the weekends now, though he never does it socially. He is totally isolated most of the time, and rarely attends family gatherings, but they are one of the few places he won't drink. He knows what the family expects of him, but I see what he does when he comes home and it worries me, but I'm not sure what to expect. I'm not sure how to approach it either, so I feel like I enable him. I'm trying to learn about the risks and educate myself now on way to help him, but really it feels sometimes like how to help myself. To feel less anxious, or less worried. I think the only thing that will do that is when he either stops altogether, or can prove that he can do it in moderation. Its just hard for me to understand, especially given how functional he still is.

Thank you for reading, its so good to get this off my chest. Perhaps some of you can help me plan my next move. 

Sincerely, JD