AN elderly couple fear for their future security after their eldest son took $20,000 of their savings before apparently killing himself and his family last week. Jobless mould master Mak Kwok-keung, 28, also left his ageing parents a $30,000 debt to loansharks. He, his wife Ma Mei-mui, 30, and daughter Wai-yee, 12, were found dead on Saturday after a gas explosion in their Shamshuipo flat. Mak Tse Luk, 70, who lives in Nam Cheong Estate, said she was unable to pay for the family's funeral arrangements. 'I don't know what happened to him. He did not smoke or drink. How would he have got into this mess?' said Mrs Mak, who had been phoned before the deaths by loansharks wanting payment of her son's debts. Mrs Mak and her husband, 75, are now dependent on the $6,000 income of her second son, who has a wife and two daughters in China. 'I am not making enough money to support myself. It is very hard for me to take care of them financially,' said the son, Mak Kwok-nang, 27. The family was given $30,000 by a Chinese newspaper two days ago and another $10,000 from the Social Welfare Department has been pledged to help meet burial costs. However, Mrs Mak fears the $40,000 may not cover the funeral and their debts. Police are still investigating the cause of death. Initial postmortem examinations failed to establish the cause.