Who is Jack Speight from She's Come Undone and what is their importance?

Jack Speight and his wife, Rita, live in Grandma Holland's upstairs apartment. Dolores is enamored with both Jack and his sports car. Jack later begins giving Dolores rides to and from school, though Dolores lies about it to her mother and grandmother. Jack is moody but Dolores deals with the changes because she's so desperate for a friend. One day, Jack takes Dolores to a deserted area near a dog kennel and rapes her. When Dolores tells, Jack and his wife sneak quietly away. There's no indication whether he told Rita of the accusation.