Wife & mother-in-law fight - who has to leave?

Divrei Rivos (Simon 140): Question:  Rachel is married to Reuven and his mother Leah lives with them in the same house. Every day Rachel has a fight with her mother-in-law Leah. Because of this Rachel claims that she doesn’t want to live with her mother-in-law Leah who she claims is the cause of all the fights and this causes her to have arguments with her husband. Does Rachel have the right to prevent Leah from living with them or not? Answer:  The Rambam (Hilchos Ishus 13:14) writes, “One who says to his wife that he doesn’t want her to bring her parents or siblings into his house – he is to be obeyed. If she wants to see them she must go to them when there is an event or once a month and every Yom Tov but they cannot go visit her unless something happens to her such as sickness or birth. That is because a person cannot be forced to allow others into his domain. Similarly if she says that she doesn’t want his parents or siblings in their home or that she doesn’t want them to live in the same courtyard because they make life unpleasant for her and bother her – she is to be obeyed. That is because we don’t force a person to live without others in his domain.” Thus we see that if they make things bad for her or bother her that she has the right to protest and prevent them from coming into her domain. This is also the ruling of the Tur (E.H. 74) and also of Rav Yerucham (#23). He adds that the Gaon wrote in a teshuva that she must be listened to and if not - she is divorced and must receive her kesuba.  Therefore in our case, if the cause of the fighting is Leah the mother-in-law then it is certain that Rachel the daughter-in-law has the right to eject her from her house and beis din will listen to her. This is so even though the Ravad wrote, “When is this so? - when they come into her domain. However if she comes into their domain they are not removed for her sake from their domain even though the home belongs to her husband and they have no rights in it. That is because her husband wants their presence. “Similarly in our case it would seem that since Reuven wants his mother in his house and Rachel his wife has come into their domain – Leah is not banished for the sake of her daughter-in-law Rachel. However this view of the Ravad is not accepted because the Magid Mishneh says about the Ravad, I say that a man does not live together with a snake. Therefore the halacha is as follows. If it appears to beis din that the relatives are bothering her and causing her to have fights with her husband – then she is right. But if not the husband’s position takes precedence over hers since it is his home and not hers. Therefore she has no right to protest except if she has a legitimate claim. This view is implied by the words of the Rambam that I mentioned before. In the part describing the husband’s rights it doesn’t mentioned any reason why he wants her family to stay away and yet he is to be listened to. In contrast in the part describing her objecting to his family coming it says because they make life unpleasant for her. Thus the Rambam is rejecting the view of the Ravad and even if Rachel is coming into their domain, if it appears to beis din that Leah the mother-in-law is causing the fights then Leah is expelled from her daughter-in-laws house. Thus we rely on the view of the Magid Mishneh since he was the most recent authority and he also saw the Ravad and yet rejected his view... Furthermore in our case if it is determined or if beis din sees that the mother-in-law Leah is the cause of the fights then the law is in accord with Rachel the daughter-in-law and we eject Leah from Rachel’s house....