I don't recommend going for an APU for any kind of decent gaming, unless you don't mind being stuck on low settings with 30 FPS.
The APU will work with the same discrete GPU's as the FX CPU's.
Well, if he doesn't plan to get a discrete GPU, because his budget is too short, he might consider the A10-6800K. Otherwise, the FX-6300 will just be much better.
If he is using a dedicated GPU there is really no reason to go with a APU. He would be better off with a AM3+ motherboard/CPU instead. As said above depending on your budget you could get a FX-6300 up to a FX-8350 it all depends on how much you have to spend. Even a FX-6300 with a good GPU would make a good gaming rig.