A mother of three was killed while vacationing with her family — in the same accident that severely injured her eldest son.

Kasey Grelle, a Missouri mom and businesswoman, was at a Nicaraguan resort with her family of five last month, when she died in a freak accident that also left her son Julian, 11, critically injured, according to her family and a report from Nicaraguan outlet TN8.

Kasey, who was 41, was traveling in a resort-owned vehicle with approximately 27 other tourists on the morning of March 23 when the vehicle lost control for unknown reasons while going down a hill, TN8 reported. The accident occurred on the premises of Rancho Santana resort in Tola, a municipality in the Rivas department of Nicaragua, per the outlet.

Announcing her death on social media, Kasey’s brother, Andy Joyce, wrote that his sibling was “on a tour put on by the resort she was staying at with her kids, Kit and Julian, when the driver lost control and rolled the vehicle, killing Kasey and severely injuring Julian.”

Kasey suffered multiple injuries, including two skull fractures, per TN8. The outlet reported that there were 20 others injured in the March 23 accident — including an American 14-year-old whose arm was amputated due to his injuries.

The National Police of Nicaragua did not immediately respond to PEOPLE’s request for comment on Sunday, April 5, nor did a spokesperson for the Rancho Santana resort.

After suffering “critical” injuries in the incident, Julian was “life flighted to St. Louis Children’s hospital,” where he “now faces a long road towards recovery,” according to a GoFundMe created to support Kasey’s family, which also includes her husband, Dave Grelle, and their kids, 9-year-old Kit and 6-year-old Desare “Des.”

As of April 1, Julian was recovering in the ICU from his injuries — which include head trauma, skull fractures, spine fractures and a collapsed lung — according to the fundraiser.

Kasey Grelle

Kasey Grelle with her family.

“True to form, he’s been cracking jokes with friends, watching the Cardinals, and tracking his March Madness bracket from his hospital bed,” the GoFundMe states. “He’s his mother’s son — tough and brave.”

As for the rest of the family, the fundraiser says: “Kit and Desare [are] home with family, making bracelets and drawings for their big brother, trying to make sense of a world that’s suddenly very different. Dave is holding everything together while his heart is broken.”

Want to keep up with the latest crime coverage? Sign up for PEOPLE’s free True Crime newsletter for breaking crime news, ongoing trial coverage and details of intriguing unsolved cases.  

Kasey’s brother said in a tribute that his sibling “was one of the most brilliant, driven and selfless people I have ever met and she was relentless in everything she did, especially when it came to helping her people.”

“We are heartbroken for David Grelle, Julian, Kit and Des as well as everyone else who knew and loved Kasey,” added Joyce.

The GoFundMe will help the family with funeral, medical and other expenses. It includes a similar message about the late mother and businesswoman.

“Kasey was a force — brilliant, driven, and passionate, with an uncanny ability to connect deeply with everyone she met,” the fundraising page states. “She founded Aux Insights, an international marketing consulting company, and served as CEO. But nothing made her prouder than being a mom.”

The GoFundMe also describes Kasey as “the family’s rock,” citing a 2016 incident in which her musician husband was almost killed in a car accident.

“Kasey spent sleepless nights at his bedside — as his wife, caregiver, and advocate — all while nine months pregnant,” the fundraiser states. “After his recovery, she became the family’s primary provider while Dave continued to heal from chronic pain. Kasey carried her family through that crisis. Now she’s gone, and they have to carry on without her.”