My mother moved in with my younger brother. She has cancer but is doing well. She is manipulating their family by being passive/aggressive. This has been her lifetime MO. This weekend she watched her granddaughter take the blame for something she did. Her granddaughter (my niece) got into tremendous trouble from her dad. My mom sat and watched and never said a word to defend her granddaughter, never took responsibility, and seemed to take pleasure in the battle. What do we do?