You can make the game window'd ( Assuming you have the enhancement pack ) and simply make a text file called setup.ini that says:
that needs to be in the same directory as the .exe file for the game...
Then, at the start of your game, put in:
Set Window On
Set Display Mode 1024,768,32
Set Window Off
That should work fine for you... Other than that, there really isn't a solution besides telling your mate to get rid of that cr*ppy software that restricts his res...
Hope I Helped...

Team EOD :: Programmer/Logical Engineer/All-Round Nice Guy