(NewsNation) — U.S. Department of Homeland Security worker Mike Downey is committed to running 50 marathons in 50 weeks to honor his teen cousin who died from a brain tumor.

While juggling a high-demand job, Downey is training to honor the memory of his cousin’s 16-year-old daughter Ella Bresee. Downey is raising money for the Children’s National Hospital Foundation in Washington, D.C., where Ella was treated and underwent surgery and 30 rounds of radiation.

He joined “Morning in America” on Tuesday, during the 42nd week of his physical challenge. Pushing past the aches and pains of training, Downey recalled Ella’s spirit and her battle with pediatric brain cancer.

“(She was) a great young lady. Only at 13 going into 14, she basically just had headaches,” Downey said. “And after looking into more and more different options and meeting with a neurologist, come to find out she had a very aggressive pediatric brain cancer called medulloblastoma.”

Downey started running about eight years ago as “something to do” and a way to “take (his) mind off everything,” he said. Inspiration struck as he approached his 50th birthday on Christmas last year.

“I touched base with my wife and thought that it would be a good idea to do 50 marathons in 50 weeks and to raise awareness and (money for) pediatric brain cancer research at the children’s hospital,” he said.

With years of training and several marathons under his belt already, Downey’s diet isn’t strict. His running, however, is “nonstop.” He replays Ella’s words with each step.

“One of the things that she always used to say was, ‘Be kind and be polite. Smile and push through’… I just keep reminding myself that her and plenty of other children don’t get a chance to push through,” Downey said. “So I just kind of keep letting that ring through my brain and just keep pushing through.”