Mario (1984)

Set during summer in the Îles-de-la-Madeleine of Quebec, Mario and Simon are two brothers living in a fishing village with their mother, who runs a grocery story, and their father, who runs a fishing business. Mario is ten years old, mute and autistic. He is withdrawn from reality and living in a surreal world that only his older brother Simon and his stuffed coyote share. Mario is very close with and deeply admires his 18 year old brother, whom he depends upon for love and attention. Simon reads Arabian Knights stories to Mario, dresses him in sheik's clothing and they play out imaginary wars in an Arabian style fortress that they built. Everything changes when Helene, a beautiful young tourist comes between the two brothers. Simon falls in love and begins to neglect his brother to spend time with her. Mario feels rejected and discovers what hate and jealously are. He sets about a chain of events that lead to tragedy.

Unfortunately the movie Mario is not yet available on HBO Max.