Hello,
If you are a Prot Paladin you can Powerlevelling a friend extremly fast in Donjon.
You will say it's common sense!
Theres is no exploit here, juste advice.
Go to Halls of Stones with your friend (76) and clean everything exept 2 last boss (event with Bronzbeard and the last one) they don't give so much money and Xp and make you loose time. Rince and repeat.
Each mob give to your friend 5k xp rested (76) 4,5k xp (7 3,5k(79) Hudge patrol 9k xp rested and boss 14k xp rested.
If you or your friend is Ingenior/Minor its interesting too! (U can mine/ingeniring a lot of mob here)
You are in stormpeaks so theres a lot of Ulduar relic, green and blue!
About 3 relic per Mob, it s faster than farming outside!
In 4h30 he takes 2lv rest (76/7 and me 246 Relic ( without my friend ones) and a lot of money in green, blue and grey.
You have to be full epic (naxx 10 is enough to clean everything), it takes between 15/25mn for one rush (without 2 last boss) depend on your stuff and if your friend is an aoe class or a healer class (both are interesting).
You can do It alone too, more time but all relic will be yours!
Don't forget you can put a tabar to earn reput!
Works well with Halls of lightning too.
Maybe this will help you to levelling your litlle brother ^^
Sorry for my bad english, hope this is understanding.
ps: This have been made without RAF and I don't use tagging mob for this, i don't know if it's possible anymore