"The doctor said he could die anytime," his mother, Jennifer Poyer, told CBS News. "It's a thickening of the muscle in the heart. It's the septum, which is the middle of the heart. And it doesn't leave enough room for the blood to get through."
Then, early last month, doctors told his parents that the Hahira, Ga., boy would have to undergo open heart surgery to install a defibrillator, reports CBS News correspondent Rebecca Jarvis.
But instead of being scared about the risky surgery, the third-grader's thoughts were on the family's finances - and the after-insurance costs of performing the operation in Atlanta, more than 300 miles away.
So, Malkolm came up with an idea to raise the money himself.
Having watched his mom run an online business, he persuaded her to put an award-winning short story he'd written in a class for gifted kids up for sale on eBay. They would sell signed, limited edition copies of his manuscript for $10 apiece.
Malkolm wound up raising more than $12,000, well beyond the $3,000 the family needed to cover its out-of-pocket costs for the operation.
"We've gotten, from the start, e-mails from people, encouraging Malkolm, and thanking him for being so inspirational to them," his mother said.
Malkolm's teacher, Theresa Hall, says she's not surprised about his courageous spirit and clever idea. "He's like a natural problem-solver," Hall observes, "and that just fits right in line."
Jennifer agrees, marveling to CBS News that, "Emotionally he's 9, but he understands things beyond his age. Sometimes I have to do a double-take and realize I'm talking to a 9-year-old because his grasp of things is so advanced."
The surgery was a success and now, Jennifer tells CBS News, Malkolm is "doing really great. … He's breathing better, moving better, more energy, and he's on his own."
On "The Early Show Saturday Edition," Jennifer told Jarvis what Malkolm did was "impressive, and I was very proud of him for being so unselfish."
Malkolm said he'd wanted to sell things on eBay before, but his parents wouldn't let him.
The story he wrote, Malkolm added, has a surprise ending - but he and Jennifer wouldn't go into any more detail!