The young man found himself in a desperate battle for his life, but through it all he stayed positive and vowed to inspire others to do whatever it takes to overcome their difficulties.
And it was that spirit that had a profound impact on the life of a former Arizona Diamondbacks player.
Most sons want to grow up to be like their father; Chris Hallsey strives to be just like his son.
"Do whatever it takes ourselves to be like him and overcome challenges like he did," said Chris Hallsey.
Tyler Hallsey was a gifted child with diverse interests.
"Loved sports, play baseball, piano, football, always a kid willing to give you a big hug and kiss, no matter how old he got," he said.
A decision to buy Diamondbacks season tickets in 2006 brought the tight-knit Hallsey family even closer.
"It turned into so much more than being fun; it bonded us as a family. The organization stepped up and made a huge difference in our lives when we needed it the most," said Chris.
Life threw the Hallsey's a curve ball in 2012, after a possible concussion and then a choking incident. Tyler wasn't himself.
"A few weeks later something was off, the spark in his eye wasn't there, he was losing his balance," he said.
Nothing could have prepared them for the diagnosis at Phoenix Children's Hospital: an inoperable tumor on his brain stem.
"Doctor came and explained and we were terrified, tears and crying, not understanding. 'Am I going to die?' he asked us after that," said Chris.
After his diagnosis, Tyler sent a message to Diamondbacks Utility Man Willie Bloomquist, who had just gotten a Twitter account.
"I'm probably the last person who would get a Twitter account, but I was talked into it by a sponsor," said Bloomquist.
Bloomquist quickly called Tyler in the hospital and then visited him the next day.
Initial shock and fear was followed by a steely determination.
"He promised me he would fight, that's when he said, 'I'll do whatever it takes dad'," said Chris.
Chris created a "Whatever It Takes" Facebook page, printed t-shirts, and made wristbands.
"I felt the need to share, and he did too. He wanted to help people," he said.
People rallied around him, including the Diamondbacks. Tyler received treats from the dugout from Bloomquist at games, a pizza party with Luis Gonzales and a Make-A-Wish trip to Disney World with Kurt and Brenda Warner.
For a year, his tumor didn't grow; however, in early 2014 he got some devastating news.
"We went in, the tumor was growing again; he cried. The doctor wiped tears from his eyes and told him we're never going to give up," said Chris.
Tyler loved to write and often journaled.
"The Diamondbacks have been truly amazing. Willie Bloomquist called to check" is the last thing Tyler wrote.
"It hit me like a ton of bricks, knowing that was the last thing he said, I don't feel deserving of that," said Bloomquist.
"Towards the end, he couldn't move anything on his body, he couldn't talk. But when he would wake up int he morning, he would wake up and his eyes were wide-open, smiling, and that was enough to give you everything you needed to get through the day," said Chris.
Tyler passed away on July 13, 2014; he was 15. Chris has kept writing Facebook posts on the page; they are honest and raw. "I have bad days and look down on my wrist. He never felt sorry for himself. I swallow it and keep going."
Chris says only 4 percent of cancer research dollars are spent on pediatric cancer research. In the past 20 years, only two new drugs have been developed to combat cancer in children.