I was about to wonder if that Orochi was another body double created by his Grandmother's Bari Bari no Fruit, but apparently she's dead. So unless someone else conveniently happened upon that fruit and joined Orochi's forces again, he's really dead.
While I am sad he's not going to get the absolute shit beat out of him, a traitor dying to another traitor is incredibly poetic.
Edit: I suppose there's also the chance that his devil fruit allows him to survive getting his head cut off due to "8 headed snake" aspect, but, I don't know. Doesn't seem properly foreshadowed at all and would really be an asspull.