I think his family should feel shame at the way they worded that announcement - to specifically exclude Flora. They had to put the boot in, even when announcing their father's death. It seems the apple really doesn't fall far from the tree.
It is ironic that he went to so much trouble to hide what he had done and yet it was the way he tried to hide it which ruined him in the public's eyes, rather than the initial wrong doing of having the affair in the first place. The cover up is what he is most remembered for.
I must admit that if my h had done this, I would hate the thought of him forming a relationship with that child - maybe it was her condition for staying with him. I hope that as a decent person, I would have recognised that child's innocence and his responsibility to her. That Mrs P appears to have condoned his actions is very telling.
Actually, I wouldn't be able to forgive a 12 year affair and therefore have no idea what his wife was thinking.