Is it permissible to invest one-third of my deceased sister's money, which was bequeathed to orphans, and use its profits to fulfill her will?

The money bequeathed to orphans is their exclusive right. It leaves the ownership of the testator immediately upon their death and becomes the property of the orphans, and it must be handed over to them immediately. The heirs do not have the right to dispose of it, withhold it, or invest it, as that would prevent the money from reaching its rightful owners and delay the delivery of the orphans' rights. The Prophet, peace and blessings be upon him, urged haste in delivering rights to their rightful owners. As for the orphan's guardian, he is permitted to invest the orphan's money in a way that benefits the orphan.