what happened to the baby in his and hers

In the Netflix series His & Hers, the baby—Anna and Jack’s infant daughter, Charlotte—dies suddenly of SIDS while Anna’s mother, Alice, is babysitting her. This tragedy shatters Anna and Jack’s marriage and is the main emotional event driving the story, including Anna’s disappearance, her estrangement from both Jack and Alice, and much of the guilt and grief that follows.