Hearthpwn

The deck's core mechanic is Kel'Thuzad. Once Kel is on the field Drakk stops attacking your minions until he draws his Drakkisath's Command. To counter this we have Reincarnate and Ancestral Spirit - both of which you cast on Kel.

Mulligan for Kel, as it's mostly impossible to beat Drakk unless you have him in the first few turns. If you have Kel, mulligan for Reincarnate or Ancestral Spirit.

Once you have Kel on the board and have cast one of the two core spells on him you basically win the game. You need to play at least one taunt so that Drakk doesn't kill Kel (or Kels, since most of the time you'll have two of him) with his minions. 

If he casts Flamestrike and damages your Kels remember to suicide ONE of your Kels into a minion so that the other Kel will resummon him with full health. 

Remember, don't fill your board with junk because then you might hinder Kel from resummoning himself and give Drakk an opening.

BUDGET PLAYERS:

You need Kel'Thuzad and Reincarnate for this to work, and if you don't have Naxx - why are you trying to beat BRM on heroic? Anyway, the same rules apply for you guys. Replace any of the other cards you don't have with big minions and taunts, it doesn't really matter what since they're just going to wait in your hand most of the time.

I hope this works, it took me one try with Kel and Reincarnate in my opening hand. Good luck!