Sounds like a perfect candidate for National Geographic Bee which is a national competition for middle and elementary school students. If his school does not offer the competition, try to work with school to set one up. You just need 6 (?) classmates/friends to have a school round.

This book "Afghanistan to Zimbabwe" is a must have for all serious bee contestants.

http://shop.nationalgeographic.com/...study-shop/books/afghanistan-to-zimbabwe