"Me and my children were watching fireworks and then all of a sudden, I see my son collapse," said the boy's mom, Hortensia Sanchez.
The incident happened just before 9 p.m. outside the family's home near E. 40th Place and Avalon Boulevard, an area that has some of the highest shooting rates compared to other parts in L.A.
Bryan Ivan Robles Jr. was standing outside watching fireworks from the yard when he was hit by the stray bullet on top of his head.
His mom said all they heard that night was the fireworks.
"All I hear is him scream... He had this scream that I never heard before. He ran towards me and he collapsed in my arms," she added.
Sanchez said she then noticed a bleeding wound on his head.
6-year-old boy critically injured after being hit by stray bullet in South LA
His mother says the left side of his brain has been damaged. The boy is currently in stable but critical condition as doctors wait for the swelling in his brain to decrease so they could see how much damage was done.
A GoFundMe has been set up to help pay for his medical expenses.
"It's a horrible thing that a 6-year-old has to go through. All he wanted to do was watch fireworks on Fourth of July like every other child," Sanchez said.
Sanchez says she's heard gunshots in her neighborhood in the past.
"I live in a neighborhood where people do whatever the hell they want to do. You heard this on the news all the time, but you never think it's going to happen to you. This is horrible."
Shootings reported in LAPD's Newton Division - analyzed by ABC7 for our Neighborhood Safety Tracker - have decreased slightly in the last 12 months, but are still higher than many years over the past decade.
Detectives say no arrests have been made and there is no description of a suspect in the ongoing investigation.