Officers say the 15-year old drove to Mountain Empire High School at around 2:25 p.m. on Wednesday and secretly picked up five friends between the ages of 14 and 15.
"He knew where Grandma kept her keys and he took the car without her knowing," said Officer Brian Pennings.
"He utilized the faculty parking lot to try to be as inconspicuous as possible," he said.
The Tahoe took off down Buckman Springs Road at a high rate of speed, according to the CHP.
But the 15 year old driver lost control on a curve and rolled the Tahoe at least three times.
"Fortunately, five of the occupants were properly restrained,"Pennings said. "Unfortunately, there was a sixth occupant who was not restrained and was riding in the back cargo area of the Chevy Tahoe."
The boy was not ejected from the Tahoe but he did suffer "significant internal injuries" that required him to be air-lifted to Children's Hospital.
The other five teens were taken to Alvarado and Grossmont hospitals with minor to moderate injuries, Pennings said.
The driver of the Tahoe faces several charges including driving without a license.
"His parents are civilly liable for his actions and the hospital bills are going to be pretty significant," Pennings said.
Get Breaking SMS Alerts: Be the first to know when news breaks:
Text SDBREAKING to 622339