"Over the next several weeks, Zach and Daniel grew closer, talking about shared experiences their families were going through, leaning on each other and supporting one another through the boys’ treatment."

"We met so many families who are still waiting for a bone marrow donor to come through as a perfect match," Fisher said. "So anyone registering today could be that match."

“I think Luka the Lion was a natural label to give this strong child who was fighting this horrible disease,” Roehrs said. “Despite all he went through, he was always happy, he was always interactive, he was very caring. He was just a wise old soul.”

"Luka was known as #LukaTheLion in honor of his bravery, brilliance, beauty, and strength. Born with a very rare primary immunodeficiency disease that may be unique to him, he fought his entire life with grace and a smile."