What is the ruling on honoring one's parents, and how should one deal with an oppressive stepmother whom the father believes over his own children, given that the father and mother are financially well-off, yet the father refuses to spend on his children?

Filial piety is obligatory even if they do wrong, and among the greatest acts of piety is to supplicate for them, especially the father. Advise him gently and kindly regarding his bad behaviors, and remind him of Allah's saying: "O you who have believed, if there comes to you a disobedient one with information, investigate, lest you harm a people out of ignorance and become, over what you have done, regretful." If he does not accept the advice, seek help from someone whose word he accepts. The stepmother who seeks to cause discord and mischief should be advised and reminded of Allah to stop her actions. The financial support of brothers who have no money is obligatory upon the father, and he is not permitted to neglect it. Communicating with the mother, visiting her, and helping her are acts of piety. Pray for her recovery.