Mi fantasma y yo (1988)

A family of three moves to a haunted house. The couple's 10-year-old son runs into the ghost of the house but isn't scared. He tells the ghost that since his father is a writer of horror novels he lost fear of horror stories. The ghost then confides in the boy that he is a lonely ghost on account of the modern world focused on so many material priorities. Child and ghost become best friends, playing together, telling stories and helping the ghost pay his rent by scaring people every month.

Unfortunately the movie Mi fantasma y yo is not yet available on HBO Max.