Bro, headphones are another neverending search for the perfect sound. As a guitarist you should know how subjective that is
I highly highly recommend going to Jaben (
http://jaben.net/) and trying out the headphones for himself. They have a huge selection, friendliest and very knowledgeable staff, and great prices. They might even be able to recommend based on what kinda music you listen to etc. Just be prepared to spend a couple hours there chit chat and testing all sorts of cool stuff.
Just warn your brother that it's a slippery slope and not to spend more than he needs
If not he will come home with thousand dollar custom shelled triple-driver earphones and an amp bigger than his iPod. :twisted: