FX 8350 is AMD's best gaming chip. In saying this, if you have the budget I'd highly suggest picking up an Intel chip if you're going to be gaming a lot as Intel's vastly superior in the processor game.
Depends on what motherboard he has. If the motherboard allow him some overclocking room then the quad core if overclocked will get very close in gaming performance. Games will not use the 8 cores from the FX 8350.