Doug Kyed is mourning a heartbreaking loss. 

The Boston Herald's NFL reporter shared that his and wife Jen Cosby-Kyed's daughter Hallie passed away from acute myeloid leukemia (AML) on Jan. 21. She was only 2 years old. 

"We're completely lost and heartbroken without Hallie," he captioned a series of images shared to Instagram on Jan. 22, which also featured photos of their 6-year-old daughter, Olivia. "Our lives will never be the same. Hallie was a special kid, and she made a positive impact on so many people she met. We were lucky to be her parents, and Olivia was fortunate to have the best baby sister."

Hallie was first diagnosed with AML—a type of blood and bone marrow cancer—in April 2023. Doug wrote in his post that Hallie had recently relapsed after having received a bone marrow transplant, and that her chemotherapy treatments after the procedure had stopped being effective.

He added, "Doctors at Boston Children's Hospital did everything they could to help Hallie, and she beat AML every day for over nine months straight." 

Doug continued with a sweet series of memories of Hallie, a tribute to how special she was. 

"Hal, my koala baby, my little Hallie Bear, my Sour Patch Kid," he wrote. "She was so beautiful, naturally funny (and knew it) and was going to be a star in dance class. Doctors, nurses and hospital staff loved seeing which princess dress she'd be wearing that day (or particular hour)."

But amid his family's heartbreak, Doug expressed his hopes that people can find motivation from who Hallie was.

"The world is a worse place without Hallie in it," he noted, before adding, "If you can take anything from Hallie today, it's to know exactly what you want and to be persistent in asking for it, whether it's going on a walk, ride in the car or wearing one particular Disney dress (usually Cruella). I'll miss rubbing her hair and kissing her head and telling her I love her the most."

Jen also shared a moving tribute for Hallie, echoing Doug's message that their daughter had a special love for life.

"She had so much life in her little body," she captioned her respective Instagram post. "Before she was diagnosed, she always woke up so excited for the day, going straight to the closet and drawers to get herself ready, saying ‘jacket, boots, hat, car!' Throughout her battle with leukemia, she always got up. She demanded to go on 800 walks in her stroller in her final week. She passed away with paint on her hands and sparkles in her hair from doing crafts."