How does Autumn's death affect Jack in the novel, The Wishing Game?

Autumn Hillard is sexually abused by her father, and she writes to Jack, having found solace in his books and his character, the Mastermind. When Jack is unable to help her escape her father, she leaves her home and tries to escape to Clock Island. Unfortunately she drowns in the process. This event traumatizes Jack both because she dies and because he is unable to bring her father to justice. Because of this, he does not write for many years.