A high school student suffered a brain injury and is in a coma after a Texas sheriff's deputy Tasered him without cause in a school hallway, the boy's mother claims in court.

Maria Acosta sued Bastrop County, its school district and Randy McMillan, a Bastrop County sheriff's officer who works as a school resource officer.

Acosta's son suffered "a severe brain hemorrhage" when McMillan Tasered him after the boy had successfully intervened to stop two girls fighting at Cedar Creek High School a week ago, the mother claims in her federal lawsuit.

Acosta's son, N.N., "stepped in to break up the fight" on Nov. 20, to stop it from escalating before police could arrive, the mother says.

School officials called McMillan and another security officer to break up the fight.

Acosta claims that her son had "diffused the situation" by the time the officers arrived.

McMillan told him to step back, and he did so, with his hands in the air, but McMillan Tasered him anyway, the mother says.

Her son struck his head on the floor as he fell, and McMillan then put the unconscious boy in handcuffs. Acosta claims school officials "delayed in calling for medical assistance even though N.N. was in an obvious emergency medical situations."

The lawsuit continues: "Eventually, school officials called for EMS and N.N. was airlifted to St. David's Medical Center, where he immediately underwent surgery to repair a severe brain hemorrhage and was placed in a medically induced coma.

"N.N. remains in a coma, and has not been able to communicate with his family since his hospitalization."

The mother claims McMillan never was in danger, and that the defendants let him work at the school even after he Tasered another student a year ago. That created a "foreseeable danger" that led to her son's injuries, she claims.

She seeks medical expenses and damages for excessive force, failure to train and discipline and civil rights and education code violations.

The family is represented by Adam Loewy.