The victim, Devyn Holmes, was in a car with a woman and another man who were playing with two guns when he was shot around 2 a.m. Sunday.
"You're making me nervous," Holmes says in the Facebook Live, captured outside a Valero gas station on Almeda and Southmore in Houston.
WATCH: Moment of man's shooting caught on camera
Police say the three were inside the car for about nine minutes before the accidental shooting.
"It ain't got no clip, bud," the man in the backseat utters in the video.
"Hey, where you from again...?"
Seconds later, Cassandra Nickcole Damper fires a shot.
The gunshot hit Holmes in the head.
Police said both passengers immediately got out of the vehicle. Officers arrived about five minutes later.
Now Holmes' family is asking for prayers.
"To me, he's my backbone," said Kendric Holmes, Devyn's brother. "To his whole family, whenever problems go down, he'll be right there to pick us all up."
Devyn is fighting for his life at Ben Taub Hospital.
The woman who fired the weapon is only being charged with tampering with evidence after police said she tried to wipe off her hands before testing for gun powder residue.