I'm not sure I'm fully on board with this theory. I'm not actively against it, of course. I just ... I need to find some kind of support for Thorm still being alive. Rhobar121 says there was some mention of Halsin having killed Thorm's daughter, but I'm not sure where that is in the game or if it's even still in, so it leaves me uncertain.
Check out Chubblot patch 5 narrator's voice line video, around 39:25, you'll get your answer.