His mother says it's the result of a violent confrontation with Sacramento police.
"He was without oxygen to his brain, now he has permanent brain damage, now he's critically ill," said Debbie Hernandez.
Hernandez says officers tased her son, John Hernandez, leaving his back scarred and his life changed forever.
"I'm very angry and sad," said Debbie Hernandez.
The Sacramento Police Department is preparing to release videos of the incident.
The department has not identified Hernandez as the suspect.
Investigators say on March 6 a "combative suspect" led officers on a chase through the Alhambra Medical Office building -- at one point reaching into his waistband and resisting as officers tried to detain him.
That's when police say they used a baton and taser.
Jerrod Hernandez says he was with his brother a day before the incident.
"I was pretty mean to him, I said get out of my car, I want you to sober up," Hernandez said.
He says his brother has struggled with drug addiction and despite efforts to get clean, he recently relapsed.
The family has hired civil rights Attorney John Burris. His office is prepared to file suit against police.
"To go from a person who's able to run to being brain-dead as a result of contact with police, that's something disturbing that we want to investigate and have exposed," said Lawyer Melissa Nold.
Sac PD says if he Hernandez recovers he could be arrested for assault and resisting arrest.
The city's Office of Public Safety and Accountability was called to the scene to conduct an independent review of the incident.
Meantime Hernandez's mother is praying her son pulls through.
"No mother should ever have to go through this or family," said Hernandez.
Sac PD says the department chose to release the videos to be transparent.
The department is not required to release the videos because this was not a police shooting.
Sac PD declined FOX40's request for an on camera interview for this story.