No, SuperGrub doesn't use gfx. That is why I told him to only use SuperGrub to boot into the Mint install, then use the the native Mint grub commands to re-install the kernel to the mbr.
It is nice to have a copy of SuperGrub around. It will boot almost anything. It also can restore the Windows mbr file. That is why I usually tell people to use SuperGrub. They will then have it if/when they need it again.
Also in this case he is going to have to edit his menu.lst to get Windows to boot and that is easier to do from the native install, especially with Mint 5 which doesn't mount partitions by default.
Different strokes for different folks I guess.