Draugr Brutes are essentially just regular Draugr that can infuse themselves with a fiery aura. Once this aura is in place, your next attack will make the Brute explode, and you'll take the damage full-on. When a Brute is ignited, then, you should hit it with a ranged attack to remove the aura before continuing the fight.
Draugrs are armed with a crude one-handed weapon, their attacks aren't exactly slow, but they're easy to see coming.
As long as you don't allow yourself to be surrounded, standard Draugr shouldn't pose much of a threat. You can either smash them into the air with a heavy attack and follow with a combo, or put your weapon away and fight them barehanded for a very quick stun finisher.
How many Draugr Brutes have you smashed into submission? Be sure to check out our fullGod of War Ragnarok guide for information on how to beat every enemy, and much more.