This works in Macs.
In Finder select any .NEF file and execute File > Get Info (command - I)
Then select Open with and Select Photoshop.
Restart your Mac.
I doubt that will help. Since he's not upgraded Camera RAW to the latest version, Photoshop simply can't read the files. The D2x NEF are not supported in the original version of ACR.
Go
here to download the Camera RAW 3.4 update for the platform of your choice.
Put the updated plugin in a folder like this (for Windows):
\Program Files\Common Files\Adobe\Plug-Ins\CS2\File Formats
or like this (for Mac):
/Library/Application Support/Adobe/Plug-Ins/CS2
Now Photoshop and Bridge should be able to understand D2x NEF files.