Cooper Roberts was shot and suffered a severed spinal cord, among other injuries, after a gunman opened fire on the July 4 parade. Seven people were killed and more than 30 others were injured. The young boy is now paralyzed from the waist down.
Roberts underwent a seventh surgery Wednesday to reclose the original bullet-induced tear in his esophagus.
When he woke up Thursday morning, there were initially positive signs such as no fever and he was breathing over the ventilator.
As the day progressed, however, the spikes of high fevers, up to 104, returned.
A CT scan revealed fluid building in his esophagus, lungs and now around his pelvis.
RELATED: Dr. Keely Roberts, Zion school superintendent, twin sons among those shot at Highland Park parade
As a result of the developments throughout the day, he remains on a ventilator and breathing tube.
"Please keep sending love and prayers to my son as he continues to fight as hard as he can," said Keely Roberts, Cooper's mother.
[Ads /]
Cooper was spiking a fever and had an elevated heart rate due to a new infection, which is being treated with medication, spokesperson Anthony Loizzi said Tuesday, adding that doctors shared that one of the boy's lungs was partially collapsed.
"I hope, and I think everyone here is hoping and praying, that he will have the best possible outcome, but it's a long road ahead," said Dr. Ana Velez-Rosborough, trauma surgeon at NorthShore University HealthSystem.
Velez-Rosborough led the team of half a dozen surgeons that saved Cooper's life in those first critical hours after the shooting.
"We did have to operate on both his abdomen and his chest because of the location in order to stop the bleeding from the aorta, which is the main blood vessel that feeds the body from the heart," she said.
Once his condition was stabilized, he was transferred to Comer Children's Hospital.
SEE MORE: Highland Park shooting: Paralyzed 8-year-old back in critical condition, completes 7th surgery
"That little kid, he is a trooper," Velez-Rosborough said.
[Ads /]
She said before July 4 she had treated adults, but no one as young as Cooper Roberts, for injuries from the type of high-powered rifle allegedly used in the shooting.
"In my opinion, as a healthcare provider and a surgeon and a person who sees these injuries, they have absolutely no place in the civilian world," she said.
Cooper's twin brother, Luke, as well as his mother, Zion Elementary School District 6 Superintendent Dr. Keely Roberts, were also shot during the attack, family said.
Luke has been treated for shrapnel wounds to a leg, was released from the hospital and is recuperating at home with his older sisters, who were not at the parade and uninjured.
Dr. Roberts was shot twice in the leg and foot. She underwent two surgeries, and, after she learned of Cooper's condition, told doctors to discharge her or said she would walk out on her own.
Friends of the family have started a GoFundMe campaign to support medical needs.
[Ads /]
A family spokesman said Cooper loves sports, especially baseball, and is a huge Milwaukee Brewers fan.
Over $1.5 million has been raised for the family as of Friday.
Moving forward, the family will provide biweekly updates on Cooper's status on Tuesdays and Fridays, Loizzi said.
Sun-Times Media contributed to this report.