"I didn't know you can die from nut allergies. I feel foolish," she said.
At least three million American children suffer from a food or digestive allergy, and the problem is growing, according to the U.S. Centers for Disease Control and Prevention. Between 1997 and 2007, the figure rose 18 percent.
Severe food allergies stem from a combination of genes, environment and possibly diet, said Dr. Kari Nadeau, associate professor of allergies and immunology at the Stanford University School of Medicine.
"We need more research to be done to help save lives," she said. "We don't have all the answers now."
As a small child, Groezinger-Fitzpatrick refused to nuts because their smell made him sick.
"It's almost like his body knew," said his mother.
Doctors later diagnosed him with an allergy to all nuts and told Groezinger- Fitzpatrick he could live a normal life. But he had to be very careful.
He wrote a bucket list at age 9. He carried an Epi-Pen. He checked food labels and questioned food service workers constantly.
But on Friday, there was no label. And his body didn't alert him to danger.
Now Groezinger-Fitzpatrick, who was on the dean's list at his college, won't be able to live in Australia with his girlfriend or work in finance.
He just might be able to cross off one of his bucket list items, though -- to save a life. He donated his organs.
"He always wanted to do something big," said his mother, as she prepared to attend his wake. More than 1,000 people were expected. "He's going out big. He's going to make others realize [they need to] be supercautious. Be your biggest advocate," she said.