To what extent can a mother intervene in the life of her married son, his home, and his wife's affairs? And is the failure to fulfill her requests in this regard considered an act of disobedience (ʿuqūq)?

Filial piety towards one's mother is among the most incumbent duties and greatest acts of devotion to Allah, as stated in the Almighty's words: "And We have enjoined upon man [care] for his parents. His mother carried him through weakness upon weakness, and his weaning is in two years. Be grateful to Me and to your parents; to Me is the [final] destination," and the Prophet Muhammad's (peace be upon him) saying: "Your mother, then your mother, then your mother, then your father." Among the good conduct of a wife towards her husband is to assist him in being dutiful to his parents, and among the good conduct of a husband towards his wife is to provide her with an independent life without harm. The mother has no right to interfere in the couple's life except through advice and counsel. The wife is commanded to obey her husband in what is right, and she is not obligated to obey or serve his mother except as an act of kindness on her part. Therefore, strive to be dutiful to your mother and treat her kindly with wisdom and gentleness, without wronging your wife or burdening her with what is not her duty. You can use equivocation in your replies to your mother, but it is not permissible to refrain from responding to her words or to speak in an improper manner, for disobedience to one's mother is one of the gravest sins.