How can a senile grandfather's money be invested so that his reward continues after his death?

The Hadith clarifies that a person's deeds cease upon death, except for three: ongoing charity (Sadaqa Jariya), knowledge from which others benefit, or a righteous child who prays for them. Among the best deeds is ongoing charity, which continues to yield rewards after death. This includes digging wells, building schools, hospitals, and mosques, leaving behind a copy of the Qur'an, building a home for a traveler, making a river flow, and other similar acts. It must be noted that the ailing grandfather's money remains his property, and it is not permissible to dispose of it except in ways that generate growth or serve his basic needs.