It looks like you/your brother are being swayed by (very powerful) marketing forces.
Whilst 'style' etc is certainly important to many I would strongly advise you research (like you have done coming here) before spending a good chunk of money on celebrity branded headphones. Whilst some people like the sound the vast majority here will not fall into that camp and it is usually true to say you are paying for a name more than a good pair of cans.
This is a good place to start if you want to compare and contrast 'celebrity' headphones: http://www.innerfidelity.com/content/celebrity-headphone-deathmatch
At the end of the day all reviews are merely one persons opinion and you may find you/yr brother loves the sound from the Soul/Monsters/etc
O.