When she found her eldest brother bleeding after a fall early one morning in May, 77-year-old Koh Um Tee immediately called her friend Wu Yu Chin.
Ms Wu remembers that phone call: "She was crying in Hokkien on the phone, saying, 'Come quick, my brother is dying, come quick!'"
The housewife, 44, is a volunteer who has known Ms Koh and her two older brothers for eight years. The siblings, all unmarried, share a three-room flat in Circuit Road.
Ms Wu was at an appointment when the call came, so she promptly dispatched her husband, Mr Michael Chua, 46, to find out what was wrong. He knew the Koh siblings well too.
He arrived at the flat to find Mr Koh Hock Seng, 83, lying in blood and urine - conscious but very, very weak. He called for an ambulance immediately.
Mr Koh had suffered a massive stroke. After more than three months in hospital, he was moved to a nursing home last month. It remains uncertain if he will ever return home.
Before his stroke, the retired deliveryman had been the most able and fit of the siblings.
He was the main caregiver to his younger brother, Hock Teck, 80, who has kidney failure and lung problems. Until last year, the cheerful older man would accompany his brother for dialysis three times a week.
Then his sister fractured a leg and needed care herself. Ms Wu arranged for a transport operator to ferry Hock Teck for dialysis, freeing Mr Koh to care for his sister. She has since recovered, but cannot walk well.
Ms Wu first got to know the family through the Buddhist Tzu Chi Foundation, where she was a volunteer, in 2005. At the time, the siblings did not have a fan or a phone in their home; they were living on their savings and survived mainly on canned food.
In the early years, she visited them almost every day.
She bought them a mobile phone and began hooking them up with various government help schemes.
"If you know where to look, there is a lot of help available for the poor," said the Taiwan-born Ms Wu, who has four children aged between three and 13. One of her sons is YouTube sensation Chua Jin Sen, known popularly as Dr Jia Jia.
The Koh siblings now receive medical and financial assistance, free transport for dialysis and subsidised meals at home.
Their home, which still holds relics such as a kerosene stove and black light switches, has been renovated and now features grab bars and non-slip tiles - paid for by the state after Ms Wu sought the help of the Housing Board and the Community Development Council.
She is now part of a team of volunteers who take turns to visit the Kohs at home and in hospital.
When The Sunday Times dropped by one recent afternoon, Ms Koh was chatting cheerfully with Ms Wu.
"Your daughter is very pretty," she said in Hokkien. "When will she come again?"
Ask the elderly woman about Ms Wu and her wizened face breaks into a wide smile. "They don't need to come, but they come anyway," she said. "And for that, I am grateful."