Well...you can either get a modchip or SOFTMOD it.
Getting a modchip can be the best route IMO but many will disagree, you have the choice between soldering or using a solderless adapter. If you know how to solder/think you can learn it then DO NOT get a solderless adapter/modchip, solder it on yourself. If for whatever reason you cannot solder (only excuse is you have no arms/blind) then by all means get a solderless adapter/chip. If you're brother and his friend's Xbox is a version 1.0-1.5 then either choose the Xenium ICE (for advanced features/functionality and proprietary on-chip OS) or go for a cheaper and simpler modchip such as the Xecuter 2.6/SmartXX LT OPX. The solderless solution would be as simple as buying a solderless adapter like the Xapter.
If it is a version 1.6 xbox(s), then go with either the two chips mentioned above but you must rebuild the LPC. Make sure you purchase the LPC rebuild board produced by SmartXX if you choose the Smartxx LT or Xenium Ice chip and choose the rebuild board made by Xecuter for the Xecuter 2.6. The solderless...err ONLY solderless solution ATM for version 1.6 Xboxs is the Spiderchip. The spider chip is cheap and easy to solder but only holds one flash of 256k...all you need reall if you think about it. Anyways yeah.
If you go for a softmod then there are a number of ways to do it...too many to list actually so run a search, but remember this: YOU CAN'T play xbox live after softmodding...you will HAVE to have a chip for xbox live play. Because there are so many methods of softmodding the xbox, there are also many ways of installing the softmod so again refer to the search button
Look for Ltools or UXE...
After you select one of the above methods of modification then you can install the applications you want
I am sure you don't have the newest of applications so be sure to download all of the newest versions of the apps from XBINS (do a search for that too) or simply download "Slayer's Autoinstaller disk" which has everything you would need. Using Slayers is simple and fast, within 5 minutes you can have a fresh prepared harddrive ready for a play opposed to after a few hours of network setup and transferring and downloading
Hope I helped.