A courageous boy battling life-threatening brain tumors received a Miracle Makeover from a designer who makes it her business to give back to suffering cancer patients. This boy was especially deserving. He started an annual toy drive—Charlie Santa Day—where he collects toys from family and friends and distributes them to kids at St. Louis Children's Hospital. "Charlie believes he was put here on this earth to help others.

Kara and John Grady weren't normally daunted by challenges. They were a Navy family, after all. They held fast to their faith and forged on.

That's how they'd managed during John's deployments in Iraq. That's how they coped with their youngest child's Neurofibromatosis-1, a disorder that causes tumors in the tissue surrounding the nerves.

At age five, Charlie had developed an inoperable brain tumor that grew around the optic nerve and made him blind in his right eye. After fifteen months of chemotherapy, Kara and John hoped their son was in the clear.

But the doctors said his next MRI scan showed three new brain tumors. Charlie, now 7, needed 50 more weeks of chemo. This time, even the Gradys were shaken. Nothing dimmed Charlie's spirit, but the chemo sessions required him to spend a lot of time in bed. His family wanted to do something to brighten his room, but couldn't afford to remodel.

So Charlie's grandmother Carol, who'd read in Guideposts about the "Miracle Makeovers" I'd done for others, e-mailed me. I'm an interior designer, and I do these inspirational projects free of charge, with the help of generous donations and hard-working volunteers (see my blog, Design Gives Back).

"The last time Charlie did chemo, his daddy installed a train track around his bedroom because he knew how happy it would make him," Carol wrote. "But the train can't run anymore because the plastic track supports have warped. We all feel like we've had the wind knocked out of us after hearing about the new tumors. I don't know if we're up to getting Charlie's train running again. Do you think you could help?"

A new train track? I could do that. I asked them to e-mail me pictures of Charlie's train tracks. When I saw what his bedroom looked like—chipped paint on the walls, old roller shades, worn-down furniture—I knew I had to do more than get his train running again.

I called the Gradys and found out more about the Missouri family. Kara and John told me Charlie has an 8-year-old brother, Liam, who shares his room, and a sister, Katie, 13.

"It's Charlie who keeps our family upbeat," Kara said.

I said to my staff, "We could totally remake his room, don't you think?"

To make it a space that's positive and fills him with hope, I asked Charlie, "What do you like best?"

Turned out Charlie also loves trucks. All kinds—dump trucks, Hummers, garbage trucks—anything big and noisy that rumbles on four wheels. His dream, he confided, was to run his own truck-repair shop. Maybe we can create some kind of theme that connects trucks and trains, I thought.

Charlie could really help bring his room to life by telling us which colors spoke to his heart. I sketched out a cartoon, called Charlie's Repair Shop, about a mechanic's shop that fixed huge trucks, all delivered by a freight train.

"Color it in for me," I said. I didn't tell him how I planned to use it. Quickly he handed me the finished product, our template for the redo. I don't think I've ever left a design meeting so inspired!

It took our construction team three days to transform Charlie's room. Most of the volunteers came from McCarthy Building Companies, a national commercial construction firm where Charlie's dad works. "McCarthy Heart Hats" they called themselves, and I saw why. They put heart and skill into their work. We ripped up the old carpet and replaced it with new wood flooring, so Charlie's beloved dachshund Hauns could stay with him (easier to clean up the aging dog's accidents). On the wall, ceiling and furniture we painted using Charlie's "heart colors" and we put up a Thomas the Tank Engine mural.

Between the windows, we hung a sign: Charlie's Repair Shop. To make the room look like a real repair shop, we used a mechanic's tool chest for a dresser. We installed a pair of corrugated aluminum panels as window awnings. We made a desk with a tabletop set on sawhorses.

The key elements were the bed designed as a huge truck and the Thomas the Tank Engine train high above on its track.

It's perfect!" Charlie said when he and his family walked into the finished room for the first time. His bed was fitted inside what looked like a giant dump truck, complete with a steering wheel, rearview mirror and odometer.

"Crawl underneath," I said. Charlie got down on his hands and knees, climbed upon an authentic mechanic's dolly and shimmied beneath. "Awesome," he said.

High above his head, almost to the ceiling, a freight train ran and whistled around the room on a sturdy metal track. Charlie grinned like a kid without a care in the world.

Liam and Katie were grinning too. Not only for Charlie. We'd remodeled their rooms as well. Their brother's illness had been hard on them. They deserved a feel-good present of their own. Liam's favorite movie is Tron, so we built him a loft bed with his own "Tron station" underneath, including a futuristic, half-moon-shaped white chair on rollers. For Katie, who was born in Italy when her parents were stationed there and loves all things Renaissance, we installed a dreamy four-poster canopy bed with pleated white curtains, soft pillows and shelves for all her books on music and art.

That first night in his redone room Kara and John asked me to tuck Charlie in. He lay back in his bed and I smoothed the comforter around him. Charlie looked up at me and said, "I love my new room. Thank you so much."

Really I should have thanked him. All I did was make his room as bright and inspiring as he is.