Levi's green superhero cape emblazoned with a bright purple "L" trails behind the two-year-old as he runs circles around his lounge room.

The hand-crafted capes are by mothers Heather Foggett, from Queanbeyan, and Teresa Hancock, from Ngunnawal, who have created Capes4Kids as a way of empowering children undergoing treatments for illnesses.

"When the capes arrived, it was likeChristmas morning," Levi and Jude's mother, Jayde Fulton, said.

"The inside of Levi's cape is of Thomas the Tank Engine … Levi is a massive Thomas fan.

"He definitely changes his persona [when he's wearing the cape] and suddenly he's doing things I don't want him to do, like jumping off furniture. He just loves wearing it."

Levi has spent much of his short life in and out of hospital and is recovering from a bone marrow transplant he had in January for a rare genetic condition known as chronic granulomatous disease (CGD), which means he cannot fight bacterial or fungal infections. Levi's one-year-old brother Jude also has CGD. The disease affects about one in 200,000 people.

It took months for a diagnosis and by the time one was made, Levi was suffering from a severe liver infection, colitis, bowel issues and anaemia. Ms Fulton was 28 weeks pregnant with Jude at the time and had no idea she was a carrier of CGD.

If she had a son, Ms Fulton was told there was a 50 per cent chance he would have CGD. If she had a daughter, there would be a one in four chance the baby girl would be a carrier.

Levi spent eight months in hospital.

Ms Fulton said there are no words to describe her gratitude towards the 26-year-old man from Germany who was a bone marrow donor for her son.

A bone marrow donor has also been found for Judeand it is hoped he can undergo a transplant at the end of the year.

Ms Fulton said her sons were an inspiration and it was initiatives like Capes4Kids that helped children – and their parents – through the difficult times.

"Anything that can distract your child while they're going through something pretty awful is just amazing," she said.

"It was one of those things that as soon as I saw the initiative, it just brought a smile to my face and almost tears of joy. These kids go through so much and anything that can give them a little bit of strength to get them through is amazing."

Capes4Kids are preparing for their official Australian launch in coming weeks. They are calling for donations of cotton material and are looking for seamstresses in the Canberra area to help make capes.