Thanks so much to all of you for your replies. OC, I was laughing out loud while reading yours - I could just hear you saying that...
Before I had time to reply, I saw H unexpectedly yesterday at MIL's (yes, playing computer games again in the middle of a workday). I was in a rush and he was on the phone, so I didn't get to talk to him. Plus, I was too exhausted to say anything, so all we said was Hi to each other.
I took everyone's advice and just emailed him back. I kept it friendly and upbeat as suggested, thanked him for keeping me in mind, commented on his work, and peace, against your advice, I did offer some advice to him, which was to just be himself and he can't go wrong. But I wrote it all in a way that supported him.
At the end, I added how proud I was about S5 and one of his new activities. Overall, it was a short but sincere and friendly email.
I emailed our family doctor the other day after I saw him to thank him for his support. He emailed back and one line brought tears to my eyes:
'The issues are correctly much more than mere testing greener pastures and in my experience, they come off at the end, jaded and in search again...unfulfilled and more broken than before.'
It was so nice to hear that coming from a trained professional (even though he's not a psychiatrist or psychologist). What a relief to have confirmation about all that we read on here. Doesn't mean it'll necessarily happen to all of us and that the outcome will be as we hope, but at least I don't feel like I'm believing in a fairy tale.
(Our doctor treats H's entire family and is aware of the disfunction that exists - he thinks that H's issues are childhood/family related.)