His love of superheroes and determination in the face of illness inspired thousands of people across the globe to follow his story.
But for a mum-of-one from Norfolk, Denver Clinton's journey with a rare form of cancer inspired her to help more poorly children.
Last year, young Denver, of Mattishall, brought the market town of Dereham to a standstill after a special superhero walk was organised in his honour.
But sadly the four-year-old, who was diagnosed with high-risk neuroblastoma in 2018, died on Valentine's Day earlier this year.
Melanie Share, a close family friend, said it was "heartbreaking" seeing how ill he became during his time in hospital.
"I was close to Denver and thought the absolute world of him," she said.
"On a visit to the hospital, he was very poorly and unable to keep his feed in so had a very upset tummy. This meant he went through lots of pairs of pjs, then ran out of clean ones.
"It got me thinking. Often children are frequently soiling their pjs through being poorly or often come in without any through A&E."
Miss Share, of Beetley, announced in April that she would be launching the pyjama appeal via the Facebook page, Denver's Pjs. She has already received more than 1,000 notifications from people offering support.
From November 1, she will be collecting sets of pyjamas to donate to the Norfolk and Norwich University Hospital's (NNUH) children's ward to deliver in time for Christmas.
She added: "[They] can make a child's stay much more comfortable and can make them smile at a really difficult time."
The 32-year-old will be collecting pyjamas in a variety of children's sizes up until December 16. They will need to be new, with the tags still on, and must not be made from fleece material or onesies.
So far she has received 80 pairs, including a donation from Tammy Abramson-Felgate, auntie of Lowestoft-based Jaymen Woolston who is also diagnosed with neuroblastoma, and 43 sets from Geoff and Su Scales, who travelled from Oxfordshire, as well as donations from local people including Hattie Rydel and Corbyn Monteiro.
- To get involved join Denver's Pjs on Facebook or alternatively bring donations every Friday during November to the Times' office, at Breckland Business Centre on Saint Withburga Lane, Dereham.
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