Maybe you just have to plow through it with them, whether they like it or not? This is their grandchild, this is who he is. Stressing the friendships he has--the ways he fits in--even as you also talk about his love of math might help, maybe?
FWIW, I know you're not alone in this. I've talked with others here on the forum who have the same problem with the grandparents. It really is common.
I think fitting in is a real and primary goal for some people. Personally, I think that's dumb. It's not a goal I ever shared, so I can't say much about it. I just always figured that I am who I am--for better or worse--and I feel the same way about my kids. Be nice, be friendly, try to make people feel happy instead of unhappy, but be who you are. If nothing else it's a timesaver for friendships if you lay it all out to people. (But then people tend to either love me or hate me, no in-between...)
I guess I think you have to decide what messages you want to telegraph to your child, how you are going to want him to feel about himself. Then you surround him with people and ideas that support that approach. And that goes for grandparents, too. They need to get on the train or get off the tracks!
But what do I know...
I'm just babbling. Maybe something here is not a total waste of time for you?
