I'll add my late opinion
For me its a mixed bag i own all the systems (use to own an xbox before it broke but im sure im getting another one this X-mas) but personally i think Xbox live makes the xbox really worth it. It really depends on your brothers taste xbox mostly excells in FPS and other shooter type games. PS2 has a good Library of almost all game genre's (lots of them have been rpg ps2 is a good choice if your brother is into RPG's)
But im gearing towards Xbox because of my love for FPS games