A 15-year-old middle school student struggled to breathe soon after he boarded a school bus Monday morning, then collapsed and died a short while later, a tragedy his family says unfolded while his younger sister’s pleas for help from the driver were ignored.

Orange County Public Schools, however, says its preliminary investigation showed the bus driver stopped the vehicle because of a “separate incident occurring in the rear of the bus” and then noticed the teenager in distress. The driver quickly contacted the dispatch center to call 911, “which is standard operating procedure,” said Michael Ollendorff, an OCPS spokesperson, in an email Wednesday.

Jasiel Sanders, a student at College Park Middle School, was pronounced dead at AdventHealth Orlando, his family said.

Jasiel, who played football, had no known medical problems, and his parents said they are waiting for autopsy results to learn the cause of death.

His 13-year-old sister was on the school bus with him and at least twice told the driver that Jasiel was having trouble breathing and needed help, according to their mother, Victoria O’Neal. The driver told the girl, who called relatives from the bus, to return to her seat, even asking “Is he playing?” she added.

“That’s my firstborn, my baby,” O’Neal said at a news conference at her attorney’s office in Orlando. “It hurts me to the core.”

Jasiel’s father, Ronald Sanders, sat nearby in tears, his head in his hand.

O’Neal and Sanders want answers about what happened to their son on Monday morning and want to determine if the bus driver was negligent or lacked training about how to respond to an emergency, said Greg Francis, their attorney.

“We’re talking to witnesses who were on the bus and saw what happened,” Francis said.

The sister’s account is troubling, he said. “That rings of negligence, that rings of a lack of training and understanding exactly what the situation is and dealing with it,” Francis added.

The family has not filed a lawsuit and may not, he said.

“Time will tell,” Francis said. “If there’s no liability here we understand, but we want to make sure we get answers.”

The Orlando Police Department said no foul play is suspected in Jasiel’s death, though the medical examiner has not yet ruled on the cause of death.

Officers and paramedics arrived at the bus, which was then parked on South Lake Orlando Parkway near a condominium complex, at about 9:40 a.m. that morning, after getting a call about a need for assistance, the department said. The teenager was then taken to the hospital.

O’Neal said she arrived at the hospital off North Orange Avenue and was told her son was gone, though her daughter told her she thought Jasiel died on the bus.

“She saw her brother take his last breath and close his eyes,” she said. “Right now, my daughter is traumatized by this.”

OCPS said its internal investigation continues.

“Our thoughts and prayers are with the family as they deal with the loss of their child,” Ollendorff said.

Jasiel’s sister told her mother that Jasiel started to breathe heavily at the bus stop off North Pine Hills Road. O’Neal wishes the driver had noticed and called for assistance as soon as he got on board.

“I’m still hurt from it,” the mother said.

Nothing her lawyer uncovers will alter things for her family.

“It’s not going to bring my son back,” O’Neal said, but it could help someone else. “No parent should go through this.”

Parents want answers after student on Orange school bus collapses, dies