So exciting about your trip, i'm happy for you! I hope you have a great time, keep us posted.
You asked how you are going to handle it when you see him in person, personally I would treat him like an acquaintance/friend. A wave if he is across the street, if you come face to face with him I wouldn't even stop to talk (just keep walking and say hi) but if you have to pause maybe a hi, how are you doing? After he responds I would say sounds good (or some such thing) and take care of yourself!
And off I would go.
You've had your talk with him, do you ever want to rehash that again while he is still not working on himself?
The truth is, he is not who you want him to be, or perhaps a better way of putting it is he is not fulfilling what you need in a relationship, perhaps he never will be capable of that, who knows? You can't know that until he is sober and in recovery for some time, a year at least probably. Being sober will not magically make him someone who can share and be empathetic and thoughtful etc.
You want him to change, the reality is you need to accept him just the way he is. An alcoholic with a lot of emotional demons. Someone who is not dealing with that and may never. But that is ok. He is not anyone's to "fix". In fact wishing him to be another way is no different than him wishing you were less sensitive and less vocal and less emotionally aware and less confident and etc etc (of course I don't know that he wishes for any of that). Well you are all those things, that's you!