"All she said was that they had something very special for Jayden to do on Sunday," said Ms Halliwell.
Ms Furley said Jayden was chosen because he is a "very special boy" and he was also the only child from the cancer ward who was well enough to do the honours.
The eight representatives from each demolition company met Jayden at a press conference today and stood protectively around his wheelchair and his mother as the weather and media closed in.
Jim Shilton of Shilton and Brown Demolition said "As an industry we are pleased we can give something back to the restoration of Christchurch's heritage buildings. Being able to offer someone like Jayden a once-in-a lifetime opportunity is an added bonus."
The other demolitions companies are March Construction, D Construction, Jurgens Demolition, Dormer Construction, Pro Tranz Contracting and Clampet Developments and Auckland's Ward Demolition.
The money will go to the Isaac Theatre Royal and the Government will match the bid amount.
Trade Me said the auction was the third most viewed auction of all time with 459,420 views, 113 bids and 243 questions asked in the question and answers.