Is it permissible to eat from the money of my mother who pays for my studies, knowing that she takes fuel vouchers for her car from the money of my father, who works as a judge applying man-made laws, and that she bought her car from selling jewelry to women who are thought to adorn themselves with it outside the home, and from taking a loan from a usurious bank?

The manner in which the mother arrives at school, or whether the car was purchased with a usurious loan, has no bearing on the permissibility of her salary from teaching. Selling jewelry to women is not absolutely forbidden; rather, it is forbidden to sell it to someone known to be using it for an act of disobedience, such as ostentatious display (tabarruj) and the like. Even if the seller knows the buyer's intention, the compensation is not forbidden according to the majority of scholars. Even if the money was acquired through an unlawful means, dealing with it is not forbidden if the person has other permissible money. What has been mentioned is nothing more than whispers (waswas (definition)) that do not necessitate the unlawfulness of the mother's money or taking from it.