Is it permissible to take from the wealth of a father who works in a court that judges by other than what Allah has revealed, and is that considered showing loyalty to him? And what about the permissibility of borrowing money from him without informing him, in light of the fatwa that permits taking from wealth mixed with lawful and unlawful elements within the limits of what is lawful?

It is not permissible to work in man-made courts that rule by other than what Allah has revealed, due to the cooperation in sin and aggression involved, unless one is compelled to do so and cannot find what suffices their basic needs and those of their dependents. In such a case, there is no harm in remaining in this work until another job is found. There is no harm in consuming from its income when one is unable to work or when combining it with studies, provided that the studies are permissible and beneficial to Muslims. There is no need to intend borrowing from this money in case of necessity, and necessity is estimated by its measure. Whatever exceeds the necessity should be spent on the affairs of Muslims.