Is it permissible to completely sever ties with the husband’s sisters who display their adornments (tabarruj) and do not heed advice, and to prevent the wife from communicating with them, due to their bad reputation and its effect on the couple, taking into account that their mother does not help in their upbringing and threatens to sever her relationship with her daughter (the wife) if contact is cut off?

The Prophet, peace and blessings be upon him, enjoined good treatment of in-laws. However, if maintaining ties with them causes discord, corruption, or undermines religious commitment, then one must uphold religious responsibilities, even if it leads to severing ties with or shunning corrupt in-laws, especially if admonition and reminder prove ineffective. One must be extremely careful not to be lax in advising and counseling; if it doesn't work, then it is advisable to take a stance of shunning them from the house. The father and brother who are traveling should be informed of the true situation, and the father should be convinced of the necessity of his return and staying with his family, and it should be the wife or a trustworthy advisor who undertakes this. It must be noted that the relationship with the wife's sisters must be within Islamic guidelines, regarding looking, mixing, and shaking hands. Their display of adornment (tabarruj), their relationship with non-mahram men, and their abandonment of prayer are major sins. It is advisable to reduce visits to the mother-in-law's house if advice proves ineffective, and they must be shunned if the relationship with them causes harm to religion, honor, or to the wife and children, while supplicating for their guidance.