Who is Jules Harding in the novel, The First Phone Call From Heaven?

Jules is the 7-year-old son of Sully. He likes the librarian, Liz, and enjoys spending time with her. Jules and his father get along well, except in one area: the phone calls. Jules is convinced that he will receive a phone call from his mother just like everyone else is receiving. Sully is devastated that his son would believe this and tries to talk to him about the possibility of it not happening. It doesn't go well and motivates Sully to discover the truth.