(CNN) -- Call it a mixed blessing -- one that may have saved an Arizona convenience store employee's life.
When Phoenix Circle K manager Jerimiah Willey was pistol-whipped during a robbery last month, he landed at St. Joseph's Hospital with a head injury that required eight staples.
"He hit me in the head twice. ... and then throughout the whole thing, he was nudging me with the gun," Willey told CNN affiliate KTVK.
The hospital did a CT scan while he was there and discovered something far worse -- a massive and potentially life-threatening brain tumor.
"They said that had this not been found and soon around the time that it was found, that he probably just would have gone to sleep one night and not been able to wake up," his wife, Alisha Willey, told the affiliate.
He is recovering from the first of what's expected to be three brain surgeries.
"It's our understanding, that because of the size, we believe there's going to be two more surgeries," his mother-in-law, Rose Gould, told CNN.
The surgery has left him partially paralyzed, with slurred speech and some loss of hearing. He's undergoing therapy.
Although the road ahead for the Willeys and their three children is uncertain, they're hopeful that the slow-growing tumor is benign and was caught before it was too late.
A fund has been set up to help pay for the family's medical expenses.
"It's hard to be thankful to somebody who was so violent," Alisha Willey said. "I'm just very blessed that my husband is still alive and that it wasn't over that morning."