May need to be reset. If you decide to go down this road, make sure you have your username and password(if it is not set to remembered) to get back onto the internet.
It could be that the wireless adapter in your sons computer is on the blink. If your sons gaming computer is a laptop(not likely) then bring it to a friends house and try to log in to their wireless to confirm if the adapter is working correctly.
Could also be spyware on his computer. Might be worth scanning for that, and even trying a system restore to the last time the wireless worked correctly.
If all of these things fail, contact your broadband provider as there could well be a fault on their end, or on the line itself.
I am having a very similar problem with my own broadband right now. It works fine through ethernet but the wireless is not functioning correctly. I have tried all the obvious steps and my internet provider reckons there is a fault in the line and will investigate on monday.
Best of luck with it.