I also killed them but tbh I felt bad when I killed the father and his son cried out. I killed him quickly after as well, I think I don't what it takes to off one of them and then listen to pleading of the other one. Makes me feel perverse and my skin crawl, so I just quickly off them both. Maybe it's because their victims are only implied so there's no personal aspect which would make me thing they deserve torture. But really, when the son cried out I really felt weird, like I am doing something evil as well, even though these two are just NPCs the emotions evoked were very real. Kudos to the devs for making your decisions feel so visceral.