Yep, your son sounds like he's in a position so similar to me. It took me a couple years but now I talk to my parents every week and we email in between if we have stuff that won't wait until the next planned phone call/Skype. I've gotten better at talking to them and honestly they've gotten better at being flexible about how and when we talk.

Things are a lot better. I hope they will be soon for you and your son too.