Tracking Drunks

Like most corner pubs, the one attached to the restaurant attracts many people who spend a lot of time there. We see the same faces just about every day, and for many hours of every day. I always assume these people have no lives outside of the pub. They do not have homes, friends or families. Their lives exist only in the context I see them in.
This theory of them having no lives was sadly proven today. There was this guy who comes into the pub darn near every day at around 2pm, we will call him Drunk. Drunk doesn't usually leave until 8pm, and always has a pint in front of him. Today, I was out for dinner and as I was leaving the restaurant, I saw a taxicab pick up him and his flat of beer up. I was amazed. I didn't know that it was possible to drink so much in the pub and to have a flat at home as well. He must be a professional.
I was also amazed that I was right about his outside life. He drank, anywhere, anytime.
So, we drove towards home. And pulling into the parking lot of the building I live in, I noticed the same cab. I was strangely excited. There was no way he could possibly live in my building!!
And he doesn't. Well, not quite.
He opened the door to what I have always assumed to be the storage shed (semi detached from the building) and stepped inside.
Now I am so curious about this man. How do I find this stuff out? I want to know about... well, I am not so sure about what it is that I want to know, but I do.