What must the questioner do after she stole money from her father—who passed away—part of which he had designated for charity, knowing that her siblings are unaware of this?

Whoever has taken money unjustly must return it to its owner for their repentance to be complete. If the wronged person dies before the money is returned, the oppressor must hand it over to the heirs of the wronged person. It is not a condition to inform the heirs of the reason for the return. The money can be returned to the father's estate if it has not been distributed, or to the heirs, each according to their share, without their knowledge, or by paying off debts on their behalf equivalent to the value of the money. As for the money that the deceased was commanded to give in charity but was not given to a poor person, it should be returned to the estate, except for obligatory Zakat, which must be paid to its rightful recipients. It is permissible for a person to give charity from their own money on behalf of their father, and the reward for that will reach him.