Is the amount the questioner took from her father's money, which is equivalent to her dowry that her father took, rightfully hers according to Sharia, and is it permissible for her to spend it on her needy siblings if she is obliged to return it?

A father does not have the right to disinherit his children or unlawfully seize their wealth. However, he may take from their wealth according to his needs. "Indeed, your children are a gift from Allah to you. He bestows upon whom He wills females, and He bestows upon whom He wills males. They and their wealth are yours if you are in need of it." It is the son's right to reclaim what the father took from his wealth unlawfully or in excess of his right. If the son took something from his father's wealth that is not his right, he must return it to him. He is not permitted to spend it on his siblings unless their sustenance is obligatory upon the father. "The pleasure of Allah is in the pleasure of the father, and the displeasure of Allah is in the displeasure of the father."