https://www.imdb.com/title/tt8745960/

As a child, shy and troubled Luke witnesses the aftermath of a mass shooting at a neighborhood coffee shop. He meets another boy among the onlookers at the scene: cool and confident Daniel, who invites him to play and quickly becomes his friend. Although adults such as Luke’s mother Claire cannot see Daniel, he appears physically real to Luke. The boys become close playmates, and their connection helps Luke cope with his parents’ divorce. Their friendship develops in an uncanny way with unforeseen consequences.

https://www.rogerebert.com/reviews/daniel-isnt-real-movie-review-2019