You're rolling the dice on stadium food if you (or your son) has celiac. Bring your own food and chow down before and after the game. I never eat in the stadium anyway. Food in the stadium for proletariat folk like me is nothing special anyway... you ain't missing much.
You have a very manageable time window to go without food, really. I'd take stadium celiac over stadium dump any day.
Well there's my midnight advice. Enjoy the game and GO BILLS!