MELBOURNE songwriter John Tragar dedicated Let Your Angel Fly to Blake Gordon-Cooke after hearing about the toddler's journey.
Blake, from Wedderburn, was just 19-months-old when he passed away in September last year.
Blake had two holes in his heart, secondary pulmonary hypertension and a mystery, still undiagnosed, rare interstitial lung disease.
"A close friend of mine told me about Blake and his story," Mr Tragar said.
"She works at a health organisation in Bendigo and said they were having the celebration, the wake for Blake in September.
"She rang me on Monday night and said the wake was on Friday and asked me if I could write a song for it.
"I read the story about Blake on Facebook and it just broke my heart to see how emotionally exhausting for the family, Diane and Paull to go through."
Mr Tragar never met Blake and still, to this day, has not met his parents Diane and Paull.
"I was just really heartbroken by it so I had a sat down, had a think about it all and Let Your Angel Fly is what came out," Mr Tragar said.
"I love the idea of the money going to HeartKids.
"I'm honoured to be a part of the project."
The track will be released on iTunes next week.
For more information visit Facebook page Blake's Million Smiles.