Elderly residential care expenses are the fees charged by the residential care home.
If the fees charged are fully met by the Comprehensive Social Security Assistance Scheme Allowance (CSSA), the taxpayer is not entitled to a deduction for elderly residential care expenses because s/he has not paid for such expenses. However, he/she may claim dependent parent allowance in respect of his/her parent provided all the relevant conditions are satisfied, including a contribution of money towards the maintenance of the parent of not less than $12,000 in the year of assessment.
If the taxpayer’s parent reached the age of 60 during the year, the taxpayer is entitled to a deduction for elderly residential care expenses paid in that year of assessment subject to the prescribed maximum amount of $100,000.
Reference: https://www.ird.gov.hk/eng/faq/erc.htm