Elijah Portillo was struggling with headaches and dizziness at school -- then his family learned he had a brain tumor at the base of his skill

A Las Vegas family is stressing the importance of parental instincts after their 11-year-old Elijah Portillo collapsed in school. While his mom and dad knew something was wrong, doctors said Elijah was fine -- then he was diagnosed with a brain tumor.

"The biggest lesson learned for us parents is, react," his dad, Richard Portillo, told Fox 5 Vegas. "A lot of people say, they're trying to get out of school or whatnot. This was not the case. He had a life-threatening condition."

Two months ago, after the middle schooler passed out in school, Portillo says doctors said it might have been due to his son's blood pressure.

But then, Elijah began experiencing "terrible headaches, nausea, and dizziness," according to a GoFundMe established to help the family pay for his medical costs.

"His mom and dad had taken him to the doctor, and his symptoms were passed off as a virus," the GoFundMe states.

Elijah's mother, Michelle, took her son to the emergency room and talked them into doing a CT scan -- and that's when they found a 3-centimeter tumor at his brain stem/spinal cord.

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Although there are many different types of brain tumors, "a tumor can move or press on sensitive tissue and block the flow of blood and other fluid, causing pain and inflammation," according to the National Institute of Neurological Disorders and Stroke. "A tumor can also block the normal flow of activity in the brain or signaling to and from the brain."

Elijah was airlifted to Primary Children's Hospital in Salt Lake City, where he underwent a 7-hour surgery to remove the tumor.

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But on Oct. 30, the family -- whose 17-year-old, Jasmine, was killed last year in a car accident, and whose son, Art, died in 2020 from COVID -- learned that Elijah's tumor was cancerous.

Now Elijah is struggling with complications that have derailed his recovery. First he fell, and "the fall caused the drainage tube that was going into his brain to be yanked out," according to the GoFundMe.

Then, he needed a feeding tube as he is "trying so hard to eat," but unable to keep anything down.

Still Elijah continues to fight, the GoFundMe explains, and he's hoping to go home to Las Vegas before returning to Utah to begin treatment.

Related: Boy's Family Learns of Brain Tumor After He Was Bumping into Furniture: 'The Prognosis Is Pretty Bleak'

"He's really looking forward to sleeping in his own bed and, most of all, hugging his mom and brothers! He misses them so much!" the GoFundMe says.

"Elijah is so strong and remarkable. Scariest experience I have ever dealt with in my life," Richard told Fox5 Vegas. "He's actually my hero."