Madam Tan Pek Eng is 75, has high blood pressure and high cholesterol and has a metal plate inserted in her knee.
But failing health has not stopped her from caring for her paraplegic, bedridden son, Mr Chun Ee Chew, 53.
The family has a maid, but Madam Tan insists on taking charge.
Every morning, she starts her day by cleaning his soiled diapers. It's a messy business and, given her age, can take up to two hours.
After washing up, she serves him breakfast. Next, she helps him exercise his legs and massages him for half an hour. When he gets bed sores, she helps change the dressing and apply medicine. "If we turn him once every three hours or so, bed sores may not occur," she said. "But I am growing old and not as efficient as I used to be."
It is what she has been doing for 25 years, ever since the second of her seven children had a motorcycle accident in 1988. And she's not about to give up.
The family maid, Ms Ngatpiati, 43, who has been helping look after Mr Chun for nearly two years, showers him and cleans his urine bag.
"But she has many other duties, so I take over as much as I can," said Madam Tan in Mandarin.
It is tiring as her son, who is paralysed on his right side, is heavy. "I have no choice."
The strong-willed woman's love for her son is obvious as she describes his motorcycle accident. "He was a good, helpful boy, taking a friend who had hurt his leg to see a doctor," she said. "He got hit by a taxi and it changed his life."
One of her younger sons, a taxi driver, his wife and teenage daughter share the flat.
"It's good to have them live with us," said Madam Tan. "I don't think I could deal with medical emergencies alone at my age."
Like his mother, Mr Chun also has high cholesterol and diabetes. Mother and son spend $350 a month on medicines.
"I feel touched that she has taken care of me for so long," Mr Chun says. "But I've had a tough life too, not being able to do so many things I want to do."
When he was better, he used to travel to Waterloo Street to sell packets of tissue paper. "But the income was very little."
He would like to move to a nursing home to spare his ageing mother the daily stresses of caring for him.
"But we must pay a lot of money. Difficult," he says.
He did not leave the flat for 11 years after his accident. The family was able to afford a wheelchair and the services of a maid only in 1999, after receiving an insurance payout for the accident.
Mr Chun tries not to think of those days, but of more pleasant times.
"Once my mother bought me two durians," he says, his face breaking into a smile for the first time. "I was so happy."