When my 8-year-old daughter Theresa got sick with a mild flu, my mother-in-law, Denise, did something she’d never done in eight years: she volunteered to help. Usually, Denise was “too busy” or had “her own life to live,” but this time, she was insistent. I should have known it was a warning sign. By midday, my phone rang. Theresa was sobbing, her breath hitching in that way that tells you a child is truly heartbroken.