What should I do regarding my father who is asking me to return the mahr (dowry) he paid me so that he can use it to marry off my brother, knowing that I am currently experiencing difficult financial circumstances and do not possess the amount, and I have previously sent him many times what he helped me with, and he is now cursing me and insulting my wife because of my refusal?

The majority of scholars hold the view that a father is not permitted to take anything from his son's wealth without his consent, unless the father is in need. However, some scholars are of the opinion that he is allowed to take from it even if he is not in need, provided that it does not harm the son or that he does not give the money to another child. Accordingly, your refusal to give your father what he asks for, if it causes you harm, is not an act of disobedience. You must honor your father and give him what does not harm you. You should apologize for what you are unable to provide with wisdom and gentleness, and strive to appease him and be patient with him, for in that lies the pleasure of Allah.