I'm thankful you found your son and he was able to turn the corner. His comment about being stuck in a box is spot on. The crazy part is we have the key to that box the entire time and are either afraid to use it, don't know how to use it, or don't want to believe it will actually open the lock.
And everyone truly is different, but I'm the same way as your son. I drank to get drunk and my whole day revolved around it. But for a long time I really didn't think it was a problem because I could afford it and I still showed up to work and did a good job. Eventually I noticed that my health was beginning to suffer and I still didn't want to believe it was because of alcohol. But in the back of my mind I knew it was.
Then I met the most wonderful person I've ever known and knew I had to quit. I continued to drink, though. But, again, in the back of my mind I knew I had to quit or the end of me was going to come sooner rather than later and I didn't want to cut my time with her short or put her through what so many other people have gone through living with an alcoholic. She never nagged me about it even though I know she didn't like it. She would talk to me and support me when I talked about quitting. And then one night she said something that I will never forget. "If you don't take care of yourself, you can't take care of anyone else." I sent it to my work email that moment and it's still the bottom email in my inbox and I see it every day. So I finally pulled the trigger on some counseling, went to AA, and made the second best decision I've ever made. I quit. The best decision I've ever made was asking her to be my wife. And I'm happier with her now than I ever thought I could be.