It all makes sense—perfect sense in the alien's mind. With their hearts open to one another like this, linked through the Mote, Carlisle can probably feel his partner's acceptance of his words. It probably makes it easier to understand the alien's reaction in the physical world; though Glacius stays tense and keeps glaring, he doesn't rebel any further or try to escape Carlisle's touch. If he seems practically locked in place, it's because he is; the otherworldly being's true self rebelling from within against the influence of the gods, holding it prisoner now, even if it means holding back the brunt of his reactions. At this point they still would not be his own, anyways, and he can only hope they'll ebb in time.

Holding himself back like this means that he cannot fully reciprocate by pressing his scar into Carlisle's palm, but at least Glacius has made a conscious decision not to push his partner away any more. It's more than he was capable of before, and it's the first step towards fully breaking free; the rest will hopefully come more easily when he's feeling better, which is what the cleric has the space to help with now.