I heard you can use it only on humanonid NPCs which means it even works on dremora, but what about draugr?

Nope.

Ugh.

It only works on NPCs. Draugr are "creatures."

My thoughts exactly. You'd think the undead would be especially susceptible to necromantic magic. Especially one that entails having a permanent resurrected minion. But, Beth and their weird sense of "balance."

Yet draugr are undead Nords and you would think they could be reanimated.

Well draugr are already dead corpses who were reanimated by something. so to me it makes sense.