All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
The money [and property] that the dead leaves behind is a right for his heirs; Allaah Says (what means): {For men is a share of what the parents and close relatives leave, and for women is a share of what the parents and close relatives leave, be it little or much - an obligatory share.}[Quran 4:7] Moreover, the Prophet said: "Whoever left an estate, it goes to his heirs." [Al-Bukhari and Muslim]
Therefore, it is an obligation to divide this house among the heirs if some of them want it to be divided. They may also rent it and divide the rent money amongst them according to their shares or whatever they agree upon. The house may also be valued according to market price and one of the heirs may take it and then give each other heir his share and the house will become his property. Or that it may be sold and each heir will take his share from its price.
However, it is not permissible for your husband to own this house without the consent of the rest of the heirs. Residing in it does not mean that he owns it. Rather, he should not live in it on his own or to rent it without the other heirs’ permission. They have the right to ask him to pay a sum in return for him dwelling in it.
On the other hand, you are not wrong in refusing to live with your mother-in-law because a wife is not obliged to dwell with anyone of her husband’s relatives. It is your right on your husband to provide you with a separate accommodation even by renting it; for more benefit, please refer to Fatwa 86132.
Similarly, it is not permissible for your mother-in-law to use part of the house and dispose of it before the house is divided and without the permission of the other heirs. Therefore, we advise you to be patient with her and advise her in a good and soft manner.
As regards the fact that your mother-in-law helps her daughter and does not help you, then she is not obliged to help you. If she helps you, then this is good, otherwise, do not bother yourself about her. It might be better for you that she does not help you, so that she will not consider it a favour to you as she might hurt you with it one day.
Allaah Knows best.