At 15, cancer meant one thing to him.
"To me, it meant that she was gone," Dubnyk said. "I didn't know that people survived cancer. It seems strange to be that naive when you're 15, but we never faced any of that sort of thing in our family before."
Thankfully, Barb's diagnosis did not end sadly, as she has been cancer free for more than a decade now. Unlike so many others, the story of how cancer has touched the Dubnyks has a happy ending.
But that doesn't mean there wasn't a struggle.
After having a grim outlook on his mom's prognosis, his parents and siblings sat Devan down and explained that cancer wasn't necessarily the death sentence he thought it was.
"Kind of how I think about things in life in general, I just immediately switched to the optimism," Dubnyk said. "They probably understood how scary it was more than I did. I went from thinking that she was going to die for sure, to when they told me that people beat cancer, that she was going to beat it for sure."
There were bumps along the way. But even as Barb battled the cancer inside of her, she never let it affect her job as mom.
Devan remembers his mom going to the far end of their home so that nobody else would hear Barb getting sick. She was still there at hockey games, making dinners and being her normal self.
"All she was concerned about was being mom and not wanting us to see her be sick," Dubnyk said. "It's just is crazy to me that somebody can be going through that and the only thing she was worried about was us.
"If I can give half of that to my kids, then they'll be doing okay."