JOSHUA, Texas -- The crowd at a Texas high school’s auditorium filled every seat in the theater, stood lined against the wall and spilled out into overflow rooms.

A casket was at the front of the theater. On the stage above it, flower arrangements, a large, blue number 33 and pictures of 15-year-old Aaron Singleton.

Singleton died after hitting his head during a football game on Nov. 3, CBS Dallas station KTVT reports.

“Look around at everybody here,” the Rev. Larry Elsea of Reece Prairie Baptist Church said during the Thursday service. “It’s packed out in the back. We have overflow rooms. And I want you to notice how many people Aaron touched in 15 years.”

Singleton was remembered by the students he played baseball and football with and the students he sang with in choir.

Several students wrote down their memories, and Youth Pastor Sam Dallas read some during the service:

“I’m never ever going to forget the way his face lit up when he was laughing.”

“He was the guy you always wanted to be around. His laugh had life and energy in it, and it would make you laugh too.”

“He became a brother to all of us.”

“To Aaron’s amazing mom: P.S. You raised a great young man.”

Singleton’s body was kept on life support until organ donor recipients were ready.

“Hey, Aaron Singleton,” his uncle Jeremy Singleton said in his eulogy. “Today, I’m proud to say you have majorly impacted many lives in more beautiful ways. Your heart saved someone’s life. Your liver saved someone’s life. Your kidneys saved two people’s lives.”

His uncle said Aaron’s brain had been donated to research for traumatic head injuries suffered on the playing field.

Elsea summed up one of the lessons from losing someone so suddenly and so young saying, “You don’t know what’s going to happen tomorrow. So don’t leave words unsaid. Tell them you love them. Just tell each other of your family you love each other. Because life is short.”