What should wives do who are harmed by the mother's condition that they (the wives) stay with their husbands and children at her (the mother's) home four days a week, while the children get tired from the repetition of these visits?

The children are not obligated to obey their mother in staying overnight with their wives and children, but doing so is better if it does not burden them. Otherwise, they are not obliged to do so. They can stay overnight individually if it does not burden them, or the mother can stay with them in rotation if she feels lonely. The matter requires a gentle discussion with the mother to clarify the hardship and to agree on a method for visits.