Definitely one of mansion scenes, but I have no idea how to trigger it! Maybe you have to do few quests outside and return, if it makes any sense? Or maybe that is the daughter scene, only original poster forgot to mention mom?
Edit: You don't get any ups or downs in morality for the mansion. Seriously? Munching on dark powers while leaving corrupt siblings abuse each other is not immoral? Even lying to them to get into known danger? And closing portal to evil realm of absolute super-doom while saving Broadfield family is not moral? WTF? And all those bugs. The whole quest is awesome, but heck it is rough.
Edit2: Another bug - dad on daughter scene plays on loop every time you enter the basement.