Bea, It was very nice of you send him birthday greetings. I hope that he will acknowledge your gesture.
I am hoping that everything will work out w/your son's trip. It could be that your h is a bit afraid of seeing his son after all of this time and doesn't know what to say. It will be an interesting trip and I really do hope that he abides by what your son as requested...no ow there.
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.