Nick Parker is the father of Bradley Parker.
His son, Bradley, had been diagnosed with ALS a few years prior. After receiving a lap chole, Bradley was in the hospital with hematochezia, blood in the stool. He decided that he would proceed with DCD, Donation after Cardiac Death. Since he was dependent on a ventilator to stay alive, he decided to have it disconnected so his heart would stop, after which his organs would be harvested. While explaining the procedure to his mom, she asked him once again if he was sure. April came in and explained where his organs would be going, which helped his mother cope.
He was taken into the OR where his breathing tube was disconnected and his heart was allowed to stop. When it stopped, his mother began to cry and held onto him. She had to be pulled away forcibly so that the transplant could proceed.
His son, Bradley, had ALS. Once his disease had progressed, Bradley decided to allow his heart to stop so his organs could be donated.