I am hoping that in your definition of "most games" you don't mean the latest and greatest games or anything like battlefield 3+. Getting a new graphics would help yes, but really with such a low level processor, all he would end up doing is bottlenecking his system anyways. But if it's a graphics card he wants, something like a GTX 750 or similar would be fine and let him play more games. In reality, he needs a much better processor if he expects to game seriously at all.
"Hey guys, I just bought this thing called a sight ward...so it's GG." - MasterA in League of Legends