Main issue will probably be minimum FPS more than anything else, most games are still GPU limited with a semi-decent CPU, especially at that res.
Usually when your CPU bottlenecked, your minimum FPS are close to your Maximum FPS, showing that its not the "graphic cards" fault, but the cpus (that you arnt getting more fps).
So no minimum fps wont be a issue for him... hes cpu bottlenecked by abit.
(he will have low max fps, and minimum fps close to his max fps)
about the resolution thingy, if hes
heavly cpu bottlenecked, playing at 1920x resolution, wont cost him much performance vs a lower resolution (because its the cpu holding him back from haveing insane high fps, not the gpu).