What is the ruling of Islamic law regarding a mother's absolute refusal to reconcile with her son's wife, her accusation of the wife practicing magic based on a friend's mere suspicion, and her deprivation of her son's inheritance and financial hardship inflicted upon him?

You must honor your mother and treat her with kindness. She is not permitted to prevent you from inheriting from your father. You should explain to her the impermissibility of falsely accusing your wife and leveling witchcraft accusations against her based solely on suspicion, advising and admonishing her with a gentle and soft approach. Furthermore, your mother is not obligated to spend on your wife; providing for her is your duty.