If you decide to reach out, you could do it by email/text and say, "I understand that you are going to be in there area. Would you like to come by our son's place or meet up for a coffee?" You can figure out how you want to word it, but keep in mind, that if he accepts you will need to listen and allow him to do most of the talking. He needs to feel "safe" in your company once again.
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.
