What is the ruling regarding the grandmother remaining with her ex-husband, after their divorce due to repeated blasphemy or explicit verbal abuse, and the children encouraging her to stay despite her knowledge of its impermissibility?

If a wife separates from her husband through the annulment (faskh) of her marriage or by her definitive divorce (baynunah), she becomes a stranger to him, and she must separate from him. It is not permissible for her to cohabitate with him in the same house unless it is a completely independent unit with its own facilities.