It was an incredibly emotional day recently for Cassondra Singleton, who met with some of the recipients of organs from her teen son who died last year after a football injury.
In November 2016, Aaron Singleton, 15, a straight-A student at Joshua High School in Texas, suffered seizures after taking a hit during a game. He was rushed to the hospital, where doctors reportedly discovered he had a blood clot and swelling in his brain.
The next day, he was taken off life support after doctors determined he was still unresponsive. Aaron Singleton's organs were donated.
On Tuesday, Cassondra Singleton of Burleson, Texas, was joined by her family and fiancé, Robert Gray, as she met with Brenda Florez, 61, of Carlsbad, New Mexico; Dustin Earley, 32, of Denison, Texas; and Mike Norton, 62, of Houston, Texas, and their close relatives at Baylor Scott and White All Saints Medical Center in Fort Worth, Texas.
Florez received a kidney and liver; Earley, a kidney and pancreas; and Norton, a heart.
"It's a sad experience but it's also a happy experience. It's something that from the very beginning I always wanted to take place," Florez said. "I always wanted to meet the family. When they contacted me and said that they were ready to meet the recipient families, I said, 'Yes.'"
On Tuesday, Singleton said that Aaron would be happy to see how he'd given life to so many others.
"It's really emotional. It's happy because [Brenda] gets to carry on, you know, with her life and with her kids and husband and family and friends and everything."
She went on, "You know, it's a little sad. It's very sad. Because I don't have my son but her and others, Brenda and others get to live life to the fullest and that means a lot to me and my family."
Norton brought a stethoscope so that Singleton and her family could listen to the new heart beating inside his chest.
Born with a heart defect in which the heart loses elasticity, Norton said he'd ended up on the transplant list after he was diagnosed with congestive heart failure.
"Everything I do for the rest of my life, Aaron is taking me there," said Norton, a landscape photographer. "I feel him every day."
ABC News' Kelley Robinson and Avianne Tan and ABC affiliate WFAA-TV contributed to this story.