Little Isla Wilkinson was just five-years-old when she passed away in the arms of her parents.
Mum Alex Williams dressed her in her Christmas pyjamas, painted her nails and plaited her long blonde hair as she counted down the hours left with her beloved daughter laying in a hospital bed.
Medics don't know why a fit and healthy young girl's heart could stop for a whole 20 minutes, leading to severe brain damage, Chronicle Live report.
Alex and dad Robert Wilkinson said goodbye to her for the last time at 5.09pm on Friday.
Alex said: "Isla passed away in the arms of her parents. It was peaceful and she looked as beautiful as she ever did.
"I went in with my princess and came out with a box and a blanket we've shared for three days.
"I don't feel alone. I do feel lost. I can't begin to think of a future without my crazy and funny Isla in it."
Isla shared an incredibly strong bond with her heartbroken big brother Aiden, nine, with the pair of them being described as "inseparable".
He is determined to give his best friend the funeral she deserves featuring a horse-drawn carriage and to make everything pink. A GoFundMe page set up by aunt, Marcia Hogan-Williams, has already raised more than £15,000.
Marcia, 39, said: "Isla and Aiden were best friends, they did everything together.
"She'd never go to sleep without her big brother Aiden. He would always get into bed with her until she drifted off.
"They would go to breakfast club and Isla would always go and sit with Aiden and his friends. They were inseparable. With Alex, they were the Three Amigos. They did everything together."
Isla had been to a Christmas party on Monday when she came home feeling unwell. After waking up the next morning with a temperature, coughing and being sick, Alex decided to take her to hospital.
But as she went to get her shoes, Isla’s heart stopped and former St John’s volunteer Alex, 42, had to perform CPR until the ambulance arrived at their home in Plains Farm, Sunderland.
Isla's heart stopped beating for around 20 minutes before medics were able to get it started again. However, the Farringdon Primary School pupil's brain had been starved of oxygen.
Isla, who also has big sister Georgie, 22, was sedated so her body wasn’t put under undue stress. But a scan revealed the devastating news there was severe brain damage and the family were told Isla had just hours to live at Newcastle’s Royal Victoria Infirmary.
Close family went in one-by-one to say their goodbyes to Isla before her parents went in to give her one last big hug.
Marcia, who has travelled from her home in Berkshire, along with brother Jemaine Williams who travelled from Wigan, said: "We are still struggling to come to terms with what has happened. We never ever imagined anything like this.
"Isla was never poorly. She was always at school. She was bursting with personality. She loved dancing and being around people.
"She had been to see Santa the night before. We're all just absolutely devastated. Alex was already prepared for Christmas and even had a stocking filled with presents for her."
To donate can visit Isla’s GoFundMe page at www.gofundme.com/f/little-isla
