Alex Novakovicâ€™s parents had to raise Â£255,000 in 11 days to pay for him to have specialist radiotherapy in America for a brain tumour.
His plight sparked an extraordinary outpouring of generosity from celebrities, companies and the public.
As a result, Alex was today packing his favourite teddy bears in a suitcase ahead of the familyâ€™s planned flight to Boston on Sunday.
He held up a homemade â€˜Thank Youâ€™ sign that he has created for well wishers.
Celebrities lending support have included singers Joss Stone and Leona Lewis, comics John Bishop and Bobby Davro, ex-England rugby star Lawrence Dallaglio, tennis legend Martina Navratilova and TV presenters Fearne Cotton and Jeff Brazier.
After Alexâ€™s story went viral on Twitter and Facebook, Sir Richard Bransonâ€™s Virgin Atlantic also gave the family free flights to America.
At the last minute, some London Marathon runners also asked sponsors to donate to the emergency appeal and hurriedly arranged fundraising events took place across the country.