Anthony McMahon, 10, and his parents will leave Guernsey on Monday for Florida, where he will undergo corrective surgery to extend his left leg in an operation paid for by islanders.
Donations are still needed for further surgery to rectify a congenital abnormality, but enough has been raised for work to start after years of waiting.
'We all tend to moan about things such as the States, but when people saw how two youngsters had been wronged by Health and Social Services, they pulled together to help in an unbelievable way and we are so grateful,' said Anthony's mother, Kerry Croxton, an account manager at Aon Insurance Guernsey.
The cost of Anthony's surgery is estimated at £120,000.
HSSD has also refused funding to Jonah Gillingham, 17, who needs drugs for a medical condition that cost £300,000 per year.
Anthony's father, Ian, manager and licensee of The Deerhound Inn, said: 'My focus at the moment is getting Anthony's operation done and bringing him safely back to Guernsey.
'But we are so grateful for the phenomenal continued support that the people of the Channel Islands are giving us.'
Money can be donated via The Friends of Anthony Thomas JustGiving page bit.ly/1RRsZ3u.
