There is a universal law on supporting the decision-making of people with mental incapability. The Enduring Powers of Attorney Ordinance (Cap. 501) allows one, while he or she is still mentally capable, to appoint an attorney to take care of his or her financial matters in the event that he or she becomes mentally incapacitated one day (Department of Justice, 2013).

References:

Department of Justice. (2013). Cap. 501 Enduring Powers of Attorney Ordinance. Hong Kong Retrieved from https://www.elegislation.gov.hk/hk/cap501.