Is it permissible to boycott the stepmother who seeks to corrupt the relationship between the father and his children and stirs up problems, knowing that the father is aware of her lies but believes her, and with the continued false swearing by both the father and his wife?

If your stepmother is harming you and trying to sow discord between you and your father, she has committed a grave sin, and your father is mistaken in believing her. We advise you to be patient with her and treat her with wisdom and gentleness. It is forbidden to shun a Muslim for more than three days. If interacting with her causes harm, you can avoid her without shunning. False swearing (al-yamin al-ghamusa) is forbidden and one of the major sins, and there is no expiation for it according to the majority of scholars; only repentance is required. You must advise your father and his wife about this. Despite all this, you must honor your father and treat him kindly, and his right to be honored is not forfeited because he believes his wife or harms you.