"Our son is proof positive that it can take the life of a young person," Cody Lyster's mother tells PEOPLE
Lyster Family
Credit: Lyster Family

When 21-year-old Cody Lyster developed coronavirus symptoms last month, everyone from his family to his team of doctors was confident he’d make a full recovery. He was a young college baseball player and had no other apparent health conditions.

But within days Lyster was hospitalized and placed on a ventilator, unable to say goodbye to his family as he lay unconscious before taking his last breath on April 8. He is now the youngest person in Colorado to die of the virus.

“They felt he was strong, his heart looked good, [because] he was a college athlete playing baseball,” his father Kevin Lyster, 49, tells PEOPLE. “He was living right and doing everything that he was supposed to be doing, and they believed he would make it through.”

Since coronavirus began to spread around the globe late last year, the disease has been especially perilous for older adults. But it has also proven deadly for a small but growing number of young people, like Dezann Romain, a 36-year-old New York City principal, and Leilani Jordan, a 27-year-old grocery store worker from Maryland.

When Kevin — a police officer at the University of Colorado Anschutz Medical Campus — tested positive for coronavirus in mid-March, the family took precautions to keep the disease from spreading inside their household. At the time, Lyster was visiting from Colorado Mesa University for spring break.

“I was down in either the basement or the family room,” Kevin says. “We made sure that if somebody was going to a common room, like the kitchen, that we’d let each other know and we did everything that we were supposed to do to stay away from each other.”

Lyster Family
Cody Lyster, in red, playing baseball
| Credit: Lyster Family

Despite their efforts, Lyster soon came down with a fever — a telltale sign he had become infected. His symptoms didn’t become alarming until a few days later on March 30, when Kevin and his wife Lea Ann found Lyster confused and “coughing badly.” His body temperature had risen to 104 degrees.

“At that point, we called the fire department and they came,” Kevin recalls. “That was the last time I saw our son alive in person.”

Lyster was quickly placed on a ventilator and taken to an intensive care unit at a nearby hospital. With his condition showing no improvement, doctors planned to move Lyster to another facility to participate in a coronavirus clinical trial, Kevin says.

With the transfer set for later in the week and since the hospital didn’t allow visitors, a nurse called the family over FaceTime so they could say a few encouraging words to Lyster. They had no idea they were actually saying their goodbyes.

Kevin received a call from the hospital late the next night.

“When I saw the number I just knew,” he recalls. “It’s every parent’s worst nightmare.”

“He died alone,” adds Lea Ann, 49, of her son, whose kidneys and heart had failed. “I mean, there was no family. There was medical staff with him, but he died without one single family member there. It’s the worst feeling ever.”

“It’s terrible,” adds Lyster’s sister Sierra, 15. “It feels terrible.”

Lyster Family
Cody and Sierra Lyster
| Credit: Lyster Family

A GoFundMe page has raised over $23,000 to help the family, who tell PEOPLE they are still in disbelief Lyster is gone.

“It just takes the life out of you,” says Kevin, speaking to PEOPLE after returning from a funeral home. “You’re not supposed to have to bury your kid, you know? It leaves a hole in your gut. That’s the best way to describe it. You have this emptiness that you can’t describe until you’ve gone through it.”

“It’s the most devastating loss ever,” adds Lea Ann.

Since Lyster’s death, the family has heard how much he impacted the lives of the people who knew him. It has provided some comfort during this heartbreaking time.

“It definitely helps knowing that my brother helped so many lives,” Sierra says. “People I didn’t even know have reached out to me and have just told him stories about my brother.”

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The family hopes Lyster’s story can convince others to take the dangers of coronavirus seriously.

“Our son is proof positive that it can take the life of a young person,” Lea Ann says. “I do think that there are a lot of younger people out there thinking, ‘I’m invincible, this can’t affect me.’ Unfortunately, our family can tell you that that’s not the case.”

“My son has a very high platform from heaven right now,” Kevin adds. “He has the message to get out to everybody across the world that you need to take this seriously and you need to stay at home.”

As of Tuesday afternoon, Colorado has seen 7,691 cases and 308 deaths attributed to coronavirus, while the U.S. has experienced 597,834 cases and 25,191 deaths, the New York Times reported.

As information about the coronavirus pandemic rapidly changes, PEOPLE is committed to providing the most recent data in our coverage. Some of the information in this story may have changed after publication. For the latest on COVID-19, readers are encouraged to use online resources from CDC, WHO, and local public health departments. To help provide doctors and nurses on the front lines with life-saving medical resources, donate to Direct Relief here.