The body of an elderly woman, who lived with her mentally disabled son, was found in their Sha Tin home at the weekend, up to a week after she died.
The 48-year-old son apparently could not understand what had happened and was left alone without food or care at the public housing flat in Sun Wai House, on Sun Tsui Estate.
The tragedy has led to calls of more support for carers of mentally disabled grown-ups.
A security guard smelled a strong odour coming from the flat during a routine patrol at about 11pm on Saturday. Through the partly open front door, the guard reportedly saw the son sitting on the floor, asking for food.
Police were called and entered the premises. The body of the mother, 77, was found on the bedroom floor, where it was reportedly starting to decompose.
Her son, who has a record of mental illness, sustained minor injuries to his hands and face. He was taken to Prince of Wales Hospital, Sha Tin, for treatment.
Police said there were no suspicious circumstances.
Neighbours described the pair as quiet and said they had been living there for more than 20 years and receiving public assistance.
One neighbour said she had not seen them for about a week and thought they had gone to the mainland to visit relatives.
Labour Party legislator Fernando Cheung Chiu-hung urged the government to provide more support for parents of adults with intellectual disabilities.
“The Social Welfare Department should send more workers to reach out to these high-risk cases in which the carers are already old and may need help themselves,” he said.
“If the carers encounter some health problems, the mentally disabled will have no ability to take care of themselves.”
Cheung said social workers could visit cases regularly and the department could provide daily services like delivering meals or doing home cleaning.
Lawmaker Shiu Ka-chun, who represents the social welfare sector, agreed and said: “The government should upgrade some homes for the elderly to house the elderly carers as well as the ageing mentally disabled they care for. With an ageing population, such a need will become more urgent.”
The Social Welfare Department said there were 16 district support centres providing one-stop services for those with disabilities. It had since November 2014 increased annual recurrent expenditure by HK$10.6 million on more staff at centres.
In April, a mother, 82,who lived with her autistic son, 55, in Sham Shui Po, was found to have been dead for six days.
In May 2014, the body of a mother, 76, who lived with her mentally disabled son, 40, in Sham Shui Po, was found after five days.