I think that his rig is fine. Sure, overkill in a few areas, but it's a decent rig.
And about the 4GB graphics card - if the GTX460 cards had come in 2GB varieties when released, then it would actually have been prudent to pick up two of those for SLI, when VRAM requirements for modern games are increasing.
GTX460 1GB SLI is still quite powerful, but bumping up against VRAM limitations in modern games. Especially something like modded Skyrim.
So if he plans to SLI in the future, two 4GB cards would probably be ideal, for the games 3 years from now.