What has Jory been told of his mother's past in the novel, If There Be Thorns?

Jory believes that his mother's parents died in a car accident. She and her younger sister had taken a bus south, where they given a place to stay with Dr. Paul Sheffield. There she started ballet lessons and met Jory's father, Julian Marquet. Jory was born soon after Julian died. His mother then married Paul Sheffield, and gave birth to Bart. Chris is his mother's third husband.