Is it obligatory to boycott the wife's family and demand that she boycott them, knowing that there is a severance of kinship ties between the two families, but the wife and her family treat us kindly?

You must maintain ties of kinship, for the people of Paradise maintain their ties of kinship, while the people of Hell sever them. Allah the Almighty says: "It is only those who are endued with understanding that pay heed. Those who fulfill the Covenant of Allah and break not the Mithaq (bond, treaty, covenant); And those who join that which Allah has commanded to be joined" (Ar-Ra'd: 19-21). And Allah the Almighty says: "And those who break the Covenant of Allah after its ratification, and sever that which Allah has commanded to be joined, and work mischief in the earth, on them is the curse, and for them is the worst of homes" (Ar-Ra'd: 25). Furthermore, Islamic law encourages communication and good treatment of all people, and this is especially emphasized concerning relatives, in-laws, or neighbors. Allah the Almighty says: "And it is He Who has created from water human beings, and has made them kindred by descent and marriage" (Al-Furqan: 54). It is not permissible for you to sever ties with them without a legitimate religious reason, because cutting off kinship ties is among the matters that Islamic law has warned against. Allah the Almighty says: "So would you perhaps, if you turned away, cause corruption on earth and sever your ties of kinship? Those are the ones whom Allah has cursed, so He made them deaf and blinded their vision" (Muhammad: 22-23). It is not permissible for a husband to ask his wife to sever ties with her family or to assist her in doing so. Maintaining ties of kinship involves obeying Allah's command and brings immediate and future benefits. The Prophet, peace and blessings be upon him, said: "Whoever wishes that his provision be expanded for him and his life be prolonged, let him maintain his ties of kinship."