"Joy Bergman is not slipping into old age with the quiet grace her children, Molly and Daniel, would prefer. She won't take their advice, and she won't take an antidepressant. Her marriage to their father, Aaron, has lasted through health and dementia, as well as some phenomenally lousy business decisions. The Bergman clan has always stuck together, growing as it incorporated in-laws, ex-in-laws, and same-sex spouses. But families don't just grow,...