There is no treatment for psychopaths.
The mom fits the description as well. She was actively trying to lead the child into saying he had heard them calling him by nodding her head at him in the affirmative. The reason being that he was never in the attic and completely out of earshot. They needed everyone to believe he’d been in that attic.
Wow what a couple of scumbag parents! They should never be allowed custody of their children ever again.