Three-year-old Ben Sandie died after being struck down with an unidentified illness which saw him slip into a coma and never wake up.
The toddler, who was born three months premature weighing little over 1lb, suffered complications at birth but survived against near impossible odds, albeit with hearing problems.
One half of twins, Ben was kept in hospital for the first five months of his life, requiring expert medical care until after his first birthday. Mum Lorraine Sandie said her newborn was small enough to fit in the palm of her hand.
But despite these early health scares, Ben made a remarkable recovery and grew into a healthy boy who never again required hospital treatment - until his final days.
On Monday, November 23, the youngster was running a temperature and was given children's medicine to ease the symptoms.
The next morning he was found unconscious in bed and died five days later at the Sick Kids Hospital.
A post-mortem failed to ascertain the cause of death and tests continue to determine what killed him.
Ms Sandie said medical answers may give the family some solace but couldn't ease the pain of losing a child.
"Whether we know what happened or not it's not going to bring him back but for the grieving process you have to know," she said.
"Whatever it was he couldn't fight it, but he held on for five days and that gave us time to say goodbye to him.
"Because of what he had been through as a baby, in the back of your mind you were thinking he would pull through.
"As a baby he was the most poorly of the twins, but he was not really in hospital again until the last days of his life.
"When the twins were born we were told they wouldn't survive. For Ben it was touch and go so many times after he was born, but he amazed everyone when he pulled through.
"It was a miracle he survived as a baby and he was a real fighter right up until the end."
In their grief the Sandies, who live in Tranent, have put off decorating their house for Christmas, which Ms Sandie said hasn't gone unnoticed by Liam, Ben's twin brother, and their baby daughter Anna.
"It's sad enough for everyone, but we have to keep things going because it's coming up to Christmas and the kids see people with decorations up around their house and don't understand why we don't," she said.
"We are taking the kids to see Santa soon and then it hits you there's one child missing."
Asked how the family were coping with the loss, Lorraine said: "During the day when you cry the kids are horrified so you can't break down during the day. But it's different at night when they are out of sight or when you get to bed.
"His brother Liam has been amazing, he points at pictures of Ben and jumps on his bed. They both had the same coat but different colours and he's taken to wearing both of them. But I suppose you don't know whether that is just because he's cold or something else."
Lorraine described Ben as a "sensitive soul" who found joy in making people smile.
"He just wanted to please people and to make you happy. Because of that people thought he was an angel. If he was put on this earth to make people happy then he did the job."
A funeral service was held at Prestongrange Parish Church on Saturday.