Is it permissible for a woman to take a wage from her mentally ill sister's inheritance in exchange for her care and service, and to spend the remainder on her home and children, and to give charity on behalf of her and her father?

If a person suffers from a mental affliction, their guardian is responsible for preserving their wealth, spending from it on the afflicted person and those whose maintenance is obligatory upon them, and giving out their zakat. Guardianship belongs to the father, then the father's executor (wasi), then the judge.

If there is no father or executor, one should refer to the Sharia judge to appoint a guardian. The guardian may hire someone to serve the afflicted person, or the guardian and their children may perform this service for a customary wage (ujrat al-mithl), without exaggeration or spending from the money for charity. A customary wage is what another person would receive if they were hired for this service.

The guardian is not permitted to dispose of the ward's money except in ways that are in the ward's interest. The guardian does not have the right to donate, give charity, or show favoritism with the ward's money. They must spend appropriately, without extravagance or stinginess.

It is not permissible to give charity from the wealth of a person who has lost their mind. The guardian must obtain guardianship from the court to dispose of the money. The guardian may spend on the afflicted person from their own money to the extent of their need and take their wage for their service at a customary rate. If any money remains, it is returned to them. If the money is insufficient, the guardian either donates the excess or refers to the judge.