Buff Brahmas have pea combs, not rose combs,, and are, or should be much lighter. Plus Rose combs sit close to the head, are covered in spikes and should have a nice extended spike or at least a nice point protuding to the back.
He is, a very handsome bird,, that is undisputable, but if anything,, if I would have to choose,, body carriage, long curving sickle tail, color and length of saddle and hackle feathers, all suggest he has brown leghorn blood in him. The sort of raised, twisty, knarley comb like he has can result from to much genetic mixing and loosing the nice pea shape.