The huge turnout wasn't that much of a surprise to Olson's family. They had already witnessed the lightning speed that mobilized their community.
"We are utterly grief stricken at the loss of our dear, sweet boy Brett," Olson's father Mike said.
Olson told the crowd of nearly how much his son loved people and loved life.
"By my estimation if you used dog years calculations as a template, I believe he lived much longer than the 20 years he actually spent on this earth," he said.
Olson's father expressed his astonishment at the way his community in Lafayette mobilized to find his son. He disappeared during a Labor Day gathering called the Chico Float.
"Then the wave began; the social media was lit up about talk about Brett's disappearance," Olson said.
Within the first four hours of posting it on Facebook, 17,000 people joined the effort. The next day, 46,000 had joined, eventually ballooning to more than 92,000 people.
"The world will not miss Brett; we will in the most deepest fundamental way, but the world must not miss the power of the focused many that helped," Olson said.
Friends say Brett's parents raised him in a positive environment, and on this night his father was still trying to turn his son's death into a positive moment.
"Everyone should hit the pause button and think about what happened in the search for Brett and how that collective energy could be used for other passionate endeavors," he said.
The funeral is scheduled for Saturday morning in Lafayette.