You have to go younger. My son is in first grade, he knows we have a PS bit he couldn't tell you what number. His friend is in kindergarten and loves his Xbox, and I'll wager a box of donuts he couldn't tell me what Xbox he has.
If he doesn't know, no way grandma and grandpa are going to be able to get him a birthday present.
If he doesn't know, no way grandma and grandpa are going to be able to get him a birthday present.