Nick knew he wanted to donate his kidney to a stranger. What the 25-year-old Army veteran didn’t know was that the stranger would turn out to be a 9-year-old boy named Aaron.

In early December, Aaron and his family got a chance to meet his kidney donor and their transplant medical team in an uplifting reunion at Memorial Transplant Institute before the holidays. The Broward child and his selfless donor became part of Memorial’s first altruistic living kidney donation to a pediatric patient in the Institute’s history.

“I was not planning on ever finding out who it was going to, but I found out about a week before my surgery it's going to a kid. I was not expecting that,” Nick said during the reunion press conference. “That hit pretty hard. I do not cry much, but I got a drip or two going down for a minute there.”

Nick said he began researching organ donation mostly out of curiosity. After doing his homework, Nick chose Memorial Transplant Institute, knowing it was one of the country’s top transplant centers and the right place to give his gift.

He traveled three hours from his home in the Florida Keys to Memorial Transplant Institute in Hollywood, FL, after learning of the team’s expertise and success record. Nick’s decision to volunteer one of his healthy kidneys changed Aaron’s life.

Watch CBS News: Florida Man Donates Kidney to Stranger

“I'm reminded that firefighters are heroes and policemen are heroes. But actually, the living donor is often the silent unsung hero and is a superhero,” said Linda Chen, MD, surgical director for the Living Donor & Pediatric Abdominal Transplant Program.

Born with posterior urethral valve obstruction (PUV)—a congenital kidney disease where tissue blocks the urethra and causes damage to the bladder and kidneys—Aaron’s kidneys gradually deteriorated as he grew older, despite years of careful monitoring and treatment.

“I want to say thank God. Thank you so much, Nick. For us, you are an angel,” said the child’s mother, Ferline Lamothe.

The reunion underscored the urgency the expert team at Memorial Transplant Institute sees every day.

More than 100,000 people in the U.S. are waiting for an organ transplant, most of them for a kidney, and about 13 people die each day before one becomes available, according to the United Network for Organ Sharing (UNOS), the group that manages the entire U.S. organ donation efforts.