Brave Harvey Mountain will be one of just a handful of children sent to the US for state-of-the-art proton beam treatment on a rare type of brain tumour.
The Cathedral Academy pupil will spend his 12th birthday over there has he undergoes the specialist therapy for up to 12 weeks in Jacksonville, Florida.
The NHS is paying £80,000 for the treatment after doctors decided it is the best option for Harvey, of Townley Road, Lupset.
But a fundraising campaign has been launched after the family realised they need more money to pay for living costs in the US and bills back home so they can be at Harvey’s side.
Mum Angela, 41, said: “The NHS pays for the treatment, flights and accommodation but we have to pay for insurance, visas and the cost of paying the bills while we’re away from home.
“We’ve been told another family went out there and they needed at £3,500.”
Harvey first had surgery two years ago for craniopharyngioma, a rare tumour which grows at the base of the brain just above pituitary gland.
After doctors discovered that the tumour had reoccurred, proton beam therapy was deemed to be the best treatment.
The therapy uses a particle accelerator to beam protons on to cancerous cells, causing less damage to surrounding tissue than conventional radiotherapy.
Because it is not routinely available in the UK, around 50 patients a year are sent abroad for treatment by the NHS.
Ms Mountain said: “He will have treatment from Monday to Friday out there.
“He might become a bit poorly and lose his hair.
“We won’t know how well it’s worked until he comes home and has a scan three months after the treatment.
“We’re hoping the proton beam treatment kills the tumour.”
Harvey will leave for America on October 23 with dad Neil, whose employer West Yorkshire Windows has launched a crowdfunding web page to raise funds for the family.
Donations can be made by searching Friends@ West Yorkshire Windows on the www.justgiving.com website.
The NHS is building two proton beam centres, in London and Manchester, but they are not expected to be open until 2018.