What is the Sharia ruling on dealing with a mother who refuses her husband's marriage to another woman, curses him and expels him from the home, incites her children to disrespect him, severs ties of kinship with the father's relatives, and rejects her eldest son's discussion of his father's wife and her children?

It is not permissible to obey one's mother in harming one's father, neglecting one's duty towards him, or severing ties of kinship. Obedience is only in what is good and lawful, and there is no obedience to a created being in disobedience to the Creator. It is obligatory to honor one's father, treat him with kindness, and maintain kinship ties. One should advise siblings to do the same with wisdom and gentleness, and it is permissible to conceal certain matters from the mother or use allusions and circumlocution when necessary. One should also advise the mother to treat her husband kindly and not neglect his rights, doing so gently and politely, without scolding or harsh words.