During the day, Diane seemed to calm Ava effortlessly. When I called to check in, I would hear my mother-in-law’s calm voice singing softly, and Ava sounded content. But at night, the tension returned. One evening, when Kevin tried to hold her, Ava’s body went rigid as if bracing for something invisible. Her tiny fists clenched. Her breathing quickened. And when he drew her to his chest, she let out a scream so intense that even Diane seemed startled.