It was one of the happiest moments in Denniston's life -- one that he would remember in 2009, when he faced a second deep, personal tragedy.
"I got a phone call from a friend and he said, 'Did you hear about Jimi?'"
Denniston had not -- and then he got the news that Flowers had died in a fall while climbing a mountain in Aspen.
"For me, losing a friend was way worse than losing the ability to use my legs. It was the saddest day of my life."
Flowers' death shook the Paralympic team to its core. Some members didn't want to compete without their beloved coach. That is when Denniston knew what he had to do.
"I asked the swimmers, 'If I apply for the position, would you all stay?'" Denniston said.
The team agreed.
"I love swimming under Dave, and I think he is a good fit," said Erik Kamber, a member of the Paralympics swimming team. "He understands each of our training needs."
Recently, Denniston was announced as the head coach of the 2012 Paralympic Resident Swim team in Colorado Springs -- the same position his mentor Flowers had before him.
Denniston said that if he had to sum up his experiences since his 2005 accident in a single word, it would be "blessed."
"I feel blessed every day," he said. "I get to coach some of the greatest athletes in the world, work with kind and wonderful people daily, and I have amazing family and friends that love me.
"I know I've lost a lot in my short life, but I also know there is no way I could ask for anything more."