You could always tell when Jack Walker was happy as his bright blue eyes “lit up” and the hint of a smile would grace his face.
The youngster, who has died at the age of seven, struggled with several illnesses that made his life far more challenging than parents Shelley, 38, and Steven, 39, ever anticipated.
Last night Mrs Walker paid tribute to her little “superhero”, as she described the various health troubles he overcame.
And she said Jack’s absence has “left a huge hole” in the life of his parents and sisters – 14-year-old Eve-Rose and Ruby, nine.
Mrs Walker said: “We thought Jack had a faulty gene, but really there was always a big question mark over that his entire life.
“He was a normal, perfect baby and we never realised what a journey his life would be.”
Jack had serious problems with his vision, and his parents were “devastated” when they were told he may go blind during a check up when he was eight weeks old.
The couple gave up work and moved from Laurencekirk to Portlethen when Jack was one, in order to be closer to Aberdeen Royal Infirmary and to Jack’s grandmother, Linda.
It wasn’t until a recording was made of his brain activity that Jack’s parents realised the extent of the toddler’s ailments.
Mrs Walker said: “I’ll never forget that first time and the look of horror on the nurse’s face when she looked at the reading. I knew things wouldn’t be easy for Jack.
“We were told he had West Syndrome – a severe and life threatening form of epilepsy.”
Doctors never found a specific reason for his condition.
Things were difficult for the “fighter” until he got a Vagus nerve stimulation (VNS) system fitted.
The treatment worked like a pacemaker for his brain – which manipulated its activity.
Jack, a Manchester United Fan, was able to begin classes at Orchard Brae School in Aberdeen.
Mr Walker said: “That was a huge milestone, when before we had no idea he would make it that long.
“The staff there were amazing – we had so many great memories there.
“He made good friends and loved the hydrotherapy pool.”
But eight months later, Jack’s body rejected his VNS which was a “huge blow” for the Walker family.
Severe seizures followed and his condition deteriorated.
In June a new VNS was put in – and Jack enjoyed a “brilliant” few months where he was able to attend more classes at school.
But recently, when grandmother Linda Russell and Mrs Walker were checking his heart rate they noticed it was lower than usual.
Thinking a simple check-up was all that was needed, they popped into Aberdeen’s Children’s Hospital.
But the seven-year-old was kept in, and a series of tests revealed he had more serious problems.
He died peacefully at home, surrounded by family, on Thursday, October 17.
Mrs Russell said: “Jack was a fighter. The doctor at hospital would tell me: Jack is in the driving seat – he writes his own book.
“You could always look in his bright blue eyes and tell when he was happy.
“Life does feel empty now – even without the sound of his machine, the house feels too quiet.”
Mrs Walker said: “He was our superhero, there’s a huge hole without him.
“We used to feel so tired all the time, our days used to begin at 5am and end at 10pm when NHS staff took over.
“It was tough – so so tough, but I’d give anything to have those days, and Jack, back.”
Jack’s funeral was held at Aberdeen Crematorium on Thursday and mourners donated £880 for the Children’s Hospices Across Scotland charity and Orchard Brae.
The Walker family would like to thank Orchard Brae School, Chas, the Archie Foundation, NHS Grampian’s neurology and respiratory departments and carer Kim Scott and her team and all friends and family who helped support Jack.