Many of Walt Disney's early movies feature a common theme of the main character losing, or having already lost, their mother- Bambi's mother was shot, Dumbo's mom was locked up and Cinderella's mom died before the film's storyline began.
These themes, like many others present in Disney films, weren't included simply to cause an emotional reaction, they were included as a nod to Disney's own life.
Walt Disney was doing so well with his animation studio by the 1940s that he bought his parents a new house, allowing them to share in his success.
But when it was discovered that the home's furnace was in need of repair Walt sent one of his studio hands over to fix it rather than calling a professional, which would prove to be a fatal act of frugality.
The housekeeper arrived one day to find Disney's parents unconscious on the floor, poisoned by a gas leak. She pulled Walt's parents outside as quickly as she could, which saved Elias Disney's life, but sadly his mother Flora was already dead.
Disney never forgave himself for making such a terrible mistake, and the theme of a dead or missing mother became a common tragic thread that connects most Disney films.