Since he's on a "high" at the moment, I would listen and tell him the trips sounds like fun. You don't have to go over the moon gushing about it. Let me ask this...how would you behave if a co-worker or a neighbor were to tell you about this trip? When you have your answer...that's how you probably should react to his comments.
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.
