Many people on this forum have recommended "Under the Influence." Maybe that would help you understand the nature of addiction and how it impacts brain chemistry in certain people. My AH's doctor just recommended a benzo to cut his craving for alcohol and tobacco. It works somewhat in cutting the physical craving, but then there's the emotional one--not sure what would fill the void there.
It's good that you have made decisions that are in your best interest. It's very hard, I know. But no amount of rationalization will enable you to figure out why your friend acts the way he does.
Good to hear from you again--and I agree with JackRussellGirl--VT is my second home (we've spent our summers there for 15 years, and my son lives in Burlington, so I feel like we're "neighbors" right off the bat!