Having been a Friend fan and ardently waiting for the new episode to air on a Thursday night, I can say that I saw the difference in his physical appearance - the bloated face and the weight gain - and I could tell it was due to alcohol. But looks like it was stronger.
I love how you the book allowed you to connect with this person at a much deeper level that some of us can't fathom. I do agree with you that the addiction is for those who had more traumatic childhood. It's a coping mechanism of sorts, an escape (like you pointed out).
I love your strength and courage to turn things around for yourself, and you continue to help others by writing about it.