What is the ruling on a daughter intervening to mend the relationship between her mother and her paternal uncle's wife after the father swore that the mother should not speak to her paternal uncle's wife, and is she sinful for doing so?

The Shari'ah has forbidden estrangement and turning away from one another among Muslims. The Prophet, peace and blessings be upon him, said: "Do not hate one another, and do not envy one another, and do not turn away from one another, and do not boycott one another. And be, O slaves of Allah, brothers. And it is not lawful for a Muslim to forsake his brother for more than three [days]." It is advised that the father consult rulings on maintaining kinship ties, and he should be gently and kindly advised to choose an appropriate time, or by gifting him a book or an audio recording that discusses maintaining kinship ties.