Is it permissible to pay a lawyer's fees for a brother who is being prosecuted from Zakat funds?

If your brother is being legally pursued due to a debt he owes, then you must advise him to pay it. It is not permissible to help him with Zakat money or other funds if he is being unjust. Rather, he should be helped by advising him and preventing him from persisting in the transgression. However, if he is being unjustly pursued and is not in debt, then if he is capable of defending himself, it is not permissible to give him Zakat. But if he cannot find the means to repel the injustice, it is permissible to assist him with Zakat money according to his need to remove the injustice from him, because Zakat requires ownership transfer.