any computer store or just get network cable and rearrange the order of the wires, there are plenty of diagrams availiable on the net. If you choose this option you will need new ends and a crimping tool.
if he dont know where to get a crossover cable, then i doubt he would be able to make one lol... but yea, call up a local computer store and ask them, usually they make them themselves, so its less spendy then staples/walmart/<insert mega store wiping out small business here>
and I doubt he'll ever be able to back up an Xbox game. Very good point, if you have no idea where to go to get a crossover cable or don't at least have the curiousity to search the net then how in the hell are you gonna read tutorials on backing up an Xbox game. I'm getting real close to my last post on here...