The vivacious young man, born with a tumour through his stomach which caused damage to the surrounding organs, had just one kidney that worked "a little bit". However, after suffering renal failure in 2012 the only options were dialysis for life, or a transplant.

Harry's father Brendan Irvine opted for the second choice, and donated one of his own kidneys to his oldest son last month.

"Harry's been in hospital seven years on and off, all the time there is something different," Harry's mum Lauren Irvine said.

"He just takes it all in his stride. He really was put here to deal with this."

Young Harry was back in hospital last week dealing with an internal infection. With a catheter in his arm, he was enjoying some time out in the Starlight room, an initiative of the Starlight Foundation.

Termed medical-free respite, the fun comes in many forms including jelly food fights and movie nights.

"It creates a little bubble that we can walk in to and forget everything," Mrs Irvine said.

"We can put all the hassles away, before we have to go back to the hospital bed and get on with it again."

Just setting eyes on Captain Neon was enough for Harry to break into a smile, in anticipation of the fun likely to ensue.

Captain Neon is one of three of the Starlight Foundation's Canberra captains who will be helping raise money for sick children at the Centenary Hospital for Women and Children on Starlight Day on Friday.

The aim of the game for the professional superheroes is to elicit a smile or a laugh from a hospital-bound child.

"It is good for the kids to take a break from all the horrible, horrible un-fun medical things that inevitably everyone has to face when they come to hospital," Captain Neon said.

"Sometimes it can be quite hard and quite sad, but a lot of the time the special thing about Starlight is you look beyond the medical stuff, and get to have fun and be about the giggles."

Starlight Day is national fundraising initiative. For more information visit starlight.org.au