I don't what OP you're reading, polly, but your responses don't seem to bear much relation to what I've read here.
What isn't known is whether the historic abuse dad's wife allegedly suffered in her childhood is something that was previously known to dad or whether she disclosed it at the time of, or immediately following, her ds's counselling session.
However, what is known is that prior to this counselling session, dad's w had formed a liaison with another man and, while telling dad that she cannot be in a relationship while she sorts herself out and leaving him to assume all of the care for their boys 24/7, she spent night after night out with the other man until the early hours before suddenly announcing to dad that she was leaving the marital home to move in with him.
You may see this as the actions of a woman who is suffering from mental illness. I see it as the actions of a woman who fell for another man and used every trick in the book to keep her h on hold until she was sure of the om's affections, whereupon she upped and left her h and her 5 sons high and dry.
The level of cunning dad's w has displayed, together with her apparent lack of concern for her 5 sons, suggests that she may have a mild form of NPD which is common in those who engage in duplicity and underhandedness but, other than this, I see no sign of any behaviour which could be caused by a psychotic condition.