'Three Us, for example,' he said.
'You'll be fine,' I said.
He was, as it turned out.
But I'm not going to tell you what he got. And this is why.
Since Thursday, my son and his friends have been sitting round trying not to talk about their results. This is because some of them didn't get the grades they hoped for. One or two, as a result, have been turned down by the universities that made them offers.
It's not the end of the world. Of course it isn't. You can retake exams. You can apply again next year. Or you can go out and get a job.
Except that there aren't many jobs around at the moment. And next year, fees for university will have trebled.
So my son and his friends haven't really been celebrating. You can't jump up and down with joy when one of your mates is struggling to cope with the shock of bad news.
But a lot of parents I know haven't been so sensitive.
It is, of course, completely OK to share brilliant news with doting grandparents and old family friends.
But you have to be careful how you broadcast your teenager's good fortune to the world at large. If you stand on the rooftop with a megaphone shouting, 'Five A*s! She got five A*s!', you're not making life any easier for the parent whose white-faced teenager feels that his or her life is in ruins.
Yes, of course we shouldn't wrap our teenagers in cotton wool. Part of growing up is learning to roll with the punches. Life throws skiploads of rubbish at you sometimes, and you need to learn how to cope.
It happens all the time – having to smile and congratulate people on fantastic news that makes you feel, by comparison, as successful as a slug.
But I'm not sure that now is the time to drive that lesson home.
Huge congratulations if your son or daughter got fantastic A-level results. They worked hard and deserve every bit of your praise.
But do us all a favour, get down off the rooftop and put away your megaphone. For a few days at least. Just until – for the sake of those who haven't been quite so lucky – the tears have dried.