Thank you, Ron Sproat!
Thanks from me too. Lydia-- I think that old David had all of new David's doubts, to start with, how could he not have... and that we're now looking at a gradual mesmerization of new David so that he welcomes the flames too, in the end. That's certainly what's going through Roger's mind, as he thinks back on David's decision to go with his mother, just before this. David's getting less and less skeptical. Roger sees the same pattern forming. (David did express some doubts in the same conversation, but it's as if his own doubts don't matter to him, and won't affect what he does.)
I also think that we're seeing Roger's attitude toward his son transform suddenly and permanently, on camera, as we watch, because of his reading of the 1867 article. He did express reluctance to have David leave for the first time, earlier in this episode, but his heart wasn't in it. He had wanted David to go, but safely. So he grumbled and cursed to himself, probably, but had to delay his moving away with Laura.
It was very different, though, when the 1867 article created in his mind the very real, very possible (even likely) image of his son being lured into being
burned alive soon ... preceded immediately by Josette having opened the book. Knowing it's all real drives it all home for him, and his humanity, buried under layers of accumulated cynical crud, shakes those layers off in an instant and remembers it can care. This is just the kind of jolt that can do this. Ron Sproat's been giving us some very unexpected DS character development.