Is my brother cheating in Yu-Gi-Oh!?

He has a Red Eyes Darkness Dragon on the field, and has a Masked Dragon and a Twin-Headed Fire Dragon in the graveyard. I destroyed his Twin-Headed Behemoth once, but he brought it back due to it's effect. He says his Red Eyes Darkness Dragon has 3000 attack because of the Masked Dragon (Dragon type), Twin-Headed Fire Dragon (Pyro type), and his Token from the Twin-Headed Behemoth. Does his Twin-Headed Fire Dragon count towards his REDD? And what about his Twin-Headed Behemoth?