Jake Knowles, from Neenton, celebrated his sixth birthday last Friday but was taken ill on November 5 while at his home with what was thought to be appendicitis.
His mother Sacha Knowles, 28, took him to the Princess Royal Hospital at Telford while his salesman father Kieran, 27, cared for their other two sons, Jayden, aged 11, and two-year-old Tommy.
But when doctors checked him over they said they could feel a mass in his body.
Jakes' grandfather John Bishop, aged 57, from Bridgnorth, went to the hospital and he said that after a visit to A&E an X-ray was taken and then an ultra-sound scan.
He said: "Jake was admitted and they found a bed on a ward and we were told it was cancer."
His grandmother Amanda Bishop, aged 49, said: "He had a CT scan and loads of tests and when doctors came round we found he was to be transferred to Birmingham Children's Hospital.
"On the Thursday he had an operation to fit a central line for chemotherapy and we were told he would face radiotherapy, an operation and then more chemotherapy.
"It seems that he has neuroblastoma which is rare in children.
"We have also been told it could be a rarer form of a fast-growing cancer.
"His mother has not come home and will stay with him but Jake might face as much as a year in hospital.
"We are not yet sure what will happen and are waiting for more talks with the doctors."
She added: "Well-wishers are now trying to raise funds to help the family financially through a JustGiving page.
"These include Zoe Thomas, who has helped organise posters and leaflets, and Leanne Biddulph who organised a raffle, and an auction of promises is being planned to be held at the Three Horseshoes at Wheathill on December 3."
The Bridgnorth community has rallied round to support Jake and his family with the Just Giving Page set up by 'Jake's Army' sailing past its £500 target – and currently standing at £2,843.
A post on the page said: "We wanted to try and help the family as best we can and come together and try and take some of the financial burden they are likely to face with the raising cost of living and coming Christmas.
"It going to be a long road for Jake's mum, dad, brothers and family. But hopefully even if it's just £1, just to help take the strain off these guys a little and help them focus on the important thing at the moment and that's Jake. A strong kind-hearted little boy, that deserves everything we can do to help."
Anyone who wishes to support the fundraising can do so by visiting justgiving.com/crowdfunding/carla-bow?utm_term=n8PPbrpQq.