Fixing a broken family (A famous films/JonJon Pizzeria roleplay fanfiction)

Everyone knows about William Afton, AKA Spingtrap. Yet nobody cared about his sister apart from him. One day his sister decides to move away to an obscure country and change her last name to Notfa.
Years later this sister dies. Her new family were at her funeral, yet nobody noticed the rabbit at the window. Nobody except her oldest son.
In the mothers will she left a book to her oldest son, and a mission. To find her brother and his family, and help them find closure.