How can i get my little brother from wasting his money on Modern Warfare 2?

He got money recently and he somehow lost his copy of Mw2 and wants to buy it again and waste his mony. We've had 3 copies of it and we are already 10th prestige and with most of the titles. I try to tell him to buy a diffrent game but he won't listen, he claims it's the best game in the world. If anybody can help me with thi problem.