Do the full sisters inherit with the younger sister in their parents' rented apartment that they left for her?

It is not permissible for parents to favor some heirs in a will, due to the Prophet's (peace be upon him) saying: "Indeed, Allah has given every rightful person his right, so there is no will for an heir." If one of them is favored, the other heirs have the right to reject the will and claim their rights, whether this will was made during the testator's health or illness. Accordingly, the parents' allocation of the apartment to their youngest daughter is not valid, and the other siblings have the right to reject this will and take their share of the apartment, whether by dividing the rent or selling the apartment and taking their right from it.