Are “THEY” really dead?

Is Doey really dead? I mean, his body is practically a liquid, at least it acts like one.

All we did during the fight was freeze him and then attack him with saws and a drill thing (idk). But we know from the chapter 4 trailer that Doey can split himself into multiple smaller parts and reform without any issue.

So once he thaws, he should be able to get back to doing what he was doing, right?