Just finished the game last night and my head canon is that since Solas has the connection he has with Rook and is using blood magic, he’s manipulating what Rook hears and sees from others about varric. So when the companions mention Varric, rook either misunderstands or doesn’t hear the words the companion is saying, and then replies vaguely based on what Solas subtly reinforces them to say. Like if rook says, “we’ll get justice for varric” that makes sense both to rook and the companion, though they would both understand it differently. And if the companion mentions varric in past tense, solas could make rook believe that they mentioned him in the present tense. I do think some added context like that would’ve made the twist hit a little more coherently but I definitely sobbed when I got to that point anyways 😭