Joey Mausser, 6, has battled leukemia for the past two years, but he was all smiles last weekend in Des Moines, Iowa, when he helped demolish a 100-year-old building while wearing a pint-sized safety jacket and hard hat.

"Fire in the hooooooole!" Joey's 5-year-old brother shrieked, showing off a mouthful of baby teeth as Joey pushed the button that set off a series of implosions.

One-by-one, the bangs echoed from inside the building. And suddenly the brick structure fell to the ground, disappearing into a cloud of dust as onlookers cheered at a job well done.

Joey's parents bid on the opportunity to let the boys blow up the building - an old nursing college - at a Blank Children's Hospital function a few months ago, Amy Varcoe, a spokeswoman for UnityPoint Health-Des Moines, which owns the hospital. Joey is expected to finish his treatment at Blank in December and "has a pretty good outlook," she said.

"The experience we've had at Blank has been amazing," the boys' father, Matthew Mausser, told ABC's Des Moines affiliate WIO-DT. "And so when we had an opportunity like this to donate some money back and pay that forward, it was a win-win for us and for our family."

Varcoe said she wasn't sure how much money the auctioned demolition brought into the hospital.

Later, Ron Gilbert of Dykon Explosive Demolition Corp handed Joey a souvenir from the day: a brick from the rubble that was so heavy that he needed two hands to hold it.

"Look at him smiling," Gilbert told the Des Moines Register. "The kid has gone through more [expletive] than you and I have…and look at him. He's happy. That's why we do this. That's why we do this."

Caption: Joey Mausser, 6, helped demolish a 100-year-old building (Credit: WOI).