Caden lost his battle against meningococcal septicaemia last week. His funeral was to take place today in Motherwell.
His school, Ladywell Primary, recorded the Christmas hymn O Holy Night and is donating the proceeds to the Meningitis Research Fund in his honour.
The song has now moved up to No12 in the UK charts. It is ranked above Adele's Skyfall, and tracks by Calvin Harris, Taylor Swift and Rita Ora.
Caden, from Cleland, near Motherwell, was diagnosed with the blood poisoning. He lost his battle for life last Tuesday at Glasgow's Yorkhill Hospital for Sick Kids.
It was then that youngsters and staff decided to record two songs on a CD for Christmas to raise cash for the charity. Pupils suggested the choir's version of O Holy Night be uploaded to iTunes.
The school plans to donate 90% of proceeds from the song to charity. The remaining 10% will go to school funds.
Head teacher Pat Ashworth said: "We hoped to sell a few hundred downloads to parents and family but we never expected it to go so high into the charts in such a short time."
Almost 50,000 people have visited a Facebook page set up by Caden's family.