Hi FGB: I have a little different take on it.
I can't recall where your son lives (close to you?) but if my AS knocked on my door coincidentally when I was home early from work, my first response would have been fear, the kind of fear when I think I am being watched - especially by someone who I know is already mad at me (you said your son was mad at you for having a hand in him being arrested).
So there you are, face-to-face with somebody unstable (drinking), whose last contact with you involved his anger, and he is asking for something. How much of an adrenaline surge did you have when you said, "no, I do not have a carton of your cigarettes?" So I think offering him a pack of your cigarettes could have been to appease the angry gods and get him off your porch so you could shut and lock your door.
If i'm even a little bit right about any of that, you might consider not opening the door like that to him for a long, long time.
I'm speaking from personal experience here. My first response to people (based on previous experience) who are high (drinking or whatever) has become fear - whether they have shown any anger toward me in the past or not. So I could be totally off in your situation. If I am, please forgive me.