To his parents, he was a miracle baby, conceived at a time when they had lost all hope.
But in a cruel twist of fate, their only son Brian Lim, 14, was taken away when he suddenly fainted on the bus to school on Tuesday morning.
Mrs Shirley Lim, 49, got a call from Clementi Woods Secondary School vice-principal about her son's collapse at about 7am that day.
He was carried down the bus to a bus stop on Clementi Avenue 6, where passers-by tried to do cardiopulmonary resuscitation (CPR) on him while waiting for the ambulance.
But Brian never regained consciousness, the couple were told.
A Singapore Civil Defence Force spokesman said Brian was sent to the National University Hospital (NUH).
"When I heard that Brian's heart stopped, a part of me stopped functioning as well," said his father, Mr Alvin Lim, 52, chief executive officer at non-profit organisation Bizlink.
"I cannot believe it. I had said goodnight to him on Monday. He towered over me and looked stronger than me.
"My son swam and biked weekly. He was so healthy. How can this happen?"
He and his wife stayed hopeful for the next few hours at NUH, praying for their son's heart and brain to start functioning again.
"Brian's body was still warm and he's still young, so the doctor made a bold decision to put him on an external heart-lung machine, in hopes of pumping oxygen into his brain to revive him," Mr Lim explained.
But at about 6pm, when a CT scan showed Brian's brain swelling, which is a sign that oxygen was not reaching his brain, he had to be taken off the heart-lung machine.
Choking back his tears, Mr Lim said: "We were hoping for a miracle."
Mr Lim was forced to accept his son's death when he had to sign his death certificate.
It stated that Brian had died of a cardiorespiratory failure - the failure of the heart and lungs to function - with the cause pending further investigation.
"It felt like I was signing his life away. My only comfort was that he finished the race of life ahead of me," he said, breaking into tears again.
Brian was doted on by his parents as he had entered the couple's lives in the most unexpected way.
With her husband's encouragement, Mrs Lim shared with The New Paper how she and her husband had been trying for a boy after three daughters, who are now aged 17, 18 and 21.
She had just one healthy fallopian tube and doctors told her she had only a 20 per cent chance of conceiving.
Brian was conceived when they were ready to give up, when Mrs Lim was 35.
The mother of four focused all her energies on her son and doted on him.
She would often offer him chocolate treats - his favourite - in exchange for his company when she goes shopping.