I support this notion... almost...
If he can manage to run CoD4 @ "high" then he will (should?) be able to run MW3 at "high" too.. seeing as the graphics in both are about the same with MW3 looking a bit "prettier" with no real impact on frames.
Crysis should play decent enough on "medium" settings also.
However, it all depends on his resolution in the end
Edit:
Looking at these, he will have no problem with CoD4 or MW3, however, Crysis proves to be a bizzle as ever.
http://tpucdn.com/reviews/Palit/GeForce_GTX_260_Sonic_216_SP/images/cod4_1920_1200.gifhttp://tpucdn.com/reviews/Palit/GeForce_GTX_260_Sonic_216_SP/images/crysis_1920_1200.gif
A slightly overclocked-out-the-box GTX260 was used as an example because its not out the reach for an average enthusiast to overclock 10%~ (more?
) so he could quite easily get this level of performance.
The good news is, the tests were ran @ "high" settings for all games with Crysis having 4x AA, too... pretty known performance killer so I expect with medium settings, he will do just fine.... so long as he leaves AA alone