Is it permissible for the wife to grant her mother power of attorney to sell the properties of the wife's deceased father, knowing that this sale may harm some heirs and sever ties of kinship?

When a person dies, the heirs must first settle their debts and execute their will (within the limits of one-third), and then distribute the remainder according to the Book of Allah. In the mentioned case, the wife receives one-eighth due to the existence of a lineal descendant, and the daughters receive two-thirds. The remaining portion is returned if the deceased has no male agnatic relatives. These Sharia rulings must be accepted. The daughters should not have filed a lawsuit against their mother, as she has a right to dutifulness and kindness, and this causes discord and the severing of kinship ties. The daughters can persuade their mother in a better way, far from conflict.