Is it permissible for a sick person to donate the surplus from their medical treatment funds to other patients, or must the donors be asked about their desire to have it returned or to give it in charity?

The disposition of surplus funds collected for a patient, beyond their needs, is determined by the donors' intention: If their intention was to give charity to the patient, then the surplus money becomes the patient's property to dispose of as they wish, and the donors have no right to reclaim it. This is based on the Prophet Muhammad's (peace be upon him) saying: "It is not permissible for a man to give a gift or a donation and then take it back, except a father from his son. The one who gives a gift and then takes it back is like a dog that eats until it is full, then vomits, and then returns to its vomit." However, if their intention was solely for the patient's treatment, or if they had no specific intention, then they have the right to reclaim the surplus or dispose of it.