According to the official report, 24-year-old Pete Jesse Rodriguez, who lives in the same Santa Fe house, was pointing the gun at the 14-year-old as part of an ill-conceived game.
Rodriguez tracked the kid's movements with the pistol before pulling the trigger and hitting him in the left thigh.
The entire incident was caught on a surveillance camera installed inside the home.
Despite the shooting taking place around 6:30 PM on Tuesday, it wasn't until 2 AM on Wednesday that the boy's mother finally brought him to Mainland Medical Center for treatment.
Hospital staff phoned the police to report the injury before transferring the teen to Memorial Hermann Hospital where he is currently recovering.
Rodriguez was subsequently arrested and charged with felony injury to a child-serious bodily injury. He is being held in lieu of a $151,500 bond.
Investigators say the mother might also face a charge of felony injury to a child by omission.