Ethan Hunt (16), a student at Burnley's Blessed Trinity RC College, is in the intensive care unit at Manchester's Wythenshawe Hospital after he contracted sepsis, a life threatening condition that flares up when the body's response to infection causes injury to its own tissues and organs.
He has been placed in an induced coma while doctors try to bring the infection under control.
And until he wakes up, Ethan, who is a keen and passionate cyclist, does not know that doctors had to make the heartbreaking decision to amputate his legs below the knee as the infection had destroyed all the tissue.
His devastated parents, Andrew and Melanie and his older sister, Jodie (24) have kept a constant bedside vigil since Ethan was rushed into hospital two weeks ago.
And a fundraising page set up by Ethan's aunt and uncle, Ben and Nicola Spencer, has raised the awesome total of Â£4,505 almost halfway to the Â£10,000 target set, in just three days.
Nicola said: "I decided to set up the fundraising page to buy new legs for Ethan for the future but there is going to be so much more he is going to need such as a wheelchair and adaptations to his home and various equipment.
"The response so far has been fantastic, we never dreamed that people would be so generous.
"We, as a family, have gone through hell and the kindness, help and support we have been shown is overwhelming and we appreciate it so much."
Manchester United fan Ethan had been suffering from flu' but seemed to be getting better in time for his dad's 40th birthday.
Forty-four-year-old Melanie, who used to work the Burnley's Tesco store, realised there was something terribly wrong when she noticed purple blotches appearing on Ethan's legs as he rested at the family home in the Brunshaw area.
Nicola said: "They couldn't wait for an ambulance so they took him to A and E themselves.
"When they arrived at the Royal Blackburn Hospital Ethan was rushed in straight away."
Ethan suffered three cardiac arrests and scans later confirmed he had sepsis, was in severe respiratory failure and had pneumonia.
He was then transferred to Wythenshawe Hospital and placed on a special ECMO machine that drains the blood from the vein, adds oxygen and removes the carbon dioxide.
It warms the blood and then returns it to the artery and “pumps” the blood through the body which allows the blood to “bypass” the heart and lungs, allowing them to rest and get better.
Ethan, who is also battling the bacterial infection MRSA, is in a stable but critical condition and doctors have not given any indication yet when they may be able to wake him from the coma.
A sporty boy with a good sense of humour Ethan is known for playing pranks and practical jokes on his family and friends.
He is studying for his GCSEs and he has two jobs, a paper round and he also works in the executive lounge at Turf Moor.
Nicola said: "He is saving up his money to buy himself a new bike.
"He loves going out riding and sometimes Melanie will ring him and he is miles away."
Jodie, who is studying at university in Lincoln, has not left her brother's side and she has made a special diary for him, writing everything down that has happened since he became ill.
Nicola said: "The hospital provided us with a book for people to write their own special message for Ethan when they visit but the diary was Jodie's idea so that when he wakes up we can tell him everything that has happened to him.
"Along with Melanie and Andrew Jodie has been at the hospital constantly and the staff there have been absolutely fantastic.
"They have even provided them with their own room to take a shower and have a break.
"We would like to say thank you to the staff, doctors and nurses who have done everything they can to save Ethan's life."
Along with the donation page, Nicola is also organising a series of fundraising events, including a curry night at the Bombay Lounge in Barrowford.
She is also appealing for raffle prizes from local shops and businesses.
Nicola has also approached Manchester United FC to ask them to send a letter of encouragement to Ethan.
Anyone who would like to make a donation to the fund is asked to go to https://www.gofundme.com/new-legs-for-ethan-hunt.
If you would like to offer a prize or help Nicola with fundraising events please email her at [email protected]