V.C. Andrews' Dollanganger Saga If There Be Thorns (2015)

In the 1980s, siblings Cathy and Christopher Dollanganger Jr. are a ballet teacher and a surgeon respectively, and living together as wife and husband and raising Cathy's two sons from different fathers, both deceased; they all go by the surname Sheffield. Teenage Jory knows about his ballet-dancer father Julian, but Bart know nothing about his father. The boys know nothing about their parents' pasts, including that their shared mother once tried to kill them so she could inherit her estranged father's vast estate and was institutionalized after having a mental breakdown. Although secrets abound in the Sheffield home, Cathy insists on adopting the young daughter of one of her ballet students who suddenly dies. Meanwhile, Cathy and Chris' mother Corrine actually moves next door to them, desperate to reconnect to her only family. She befriends vulnerable, impressionable Bart--but so does an anything-but-innocent bystander who lives by the fire-and-brimstone beliefs of Corrine's long-deceased father Malcolm Foxworth. He teaches Bart these beliefs and encourages him to live by them and pass them on. In the meantime, he acquaints Bart with Foxworth family history..—Huggo