He can't face you because he knows that he screwed up royally and is quite uncomfortable facing you. You have shown him just how strong and independent you are and how great you are as a parent....look what he has now....starting over w/a new family and a baby that will keep him up all hours of the night (at his age, no less). He will never admit it, but he knows that he screwed up and yes, guilt for the way he has treated you since he flew the coop doesn't help him either.
I'm very pleased to see that he is acting like a civil human being for now. Let's hope it's a permanent condition and not one just for the short duration.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.