Four Denton County families are filing a lawsuit against the employer of a truck driver who is now behind bars for a drunk driving crash that killed a 13-year-old boy.

It happened around 2 p.m. on July 17 on U.S. Highway 377 in Western Grayson County.

Luis Guima was driving a pickup truck with his teenagers Gaspar Guima, Brian Duarte and their friend Angel Meza.

They were headed back from lunch to a summer construction job when a commercial truck coming from the other way lost control, over-corrected and hit their driver side.

"I remember the driver screaming and me peeking over. And when I peeked over, I just saw the semi coming straight at us," said Angel Meza.

The truck the boys were in flipped several times before coming to a rest. Their youngest passenger, 13-year-old Brian, was knocked unconscious.

"I was carrying him. I shook him up, screamed at him and tried to wake him up. He wouldn't wake up. He wouldn't move. He was just hanging out of my arms," said Gaspar Guima.

But Guima says he didn't know Brian was gone, until he heard EMTs confirm it once they were in the ambulance.

According to the incident report, the other truck's driver Christopher Downing says he fell asleep at the wheel. He also admitted to police he was under the influence of both drugs and alcohol. Downing was arrested for intoxication manslaughter and three counts of aggravated assault with a deadly weapon.

A lawsuit filed by the families in the U.S. District Court in Sherman, Downing's employer Diamond Energy Services of Tulsa is also negligent. It claims not only was Downing under the influence, but he was also driving an unregistered vehicle.

"Diamond Energy employed the driver. Diamond Energy owned the vehicle. They were responsible for putting a capable, fully trained driver in the cab of their vehicle before they put him on the roadway," said attorney Tom Carse.

The lawsuit seeks compensation for the wrongful death of Brian and the physical and mental injuries inflicted on the other three passengers.

"Bryan's parents are broken, absolutely broken hearted. There's no other way to describe it. They're devastated and reminded everyday about the loss of their son," said Carse.

Diamond Energy Service's owner said Thursday that the company policy doesn't allow him to comment on pending litigation.