Well, if I were in your shoes, I would still go on the Mexican vacation if he cancels out. You could always ask a family member or a friend to go along w/you. I certainly wouldn't allow him to ruin my vacation just because he can't get himself together.
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.