Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
If the cost of the house is less than one third of the property of the dead person, or equal to it then the will is valid in Islamic Shariah. The Will that exceeds one third of the property of a dead person is not valid except if his/her inheritors permit it and provided they are mature and prudent. The remaining property, after fulfilling the will, would be distributed among the heirs according to their prescribed shares in Shariah.
If a person dies and does not have other than his nephews (children of his brother) they will inherit from him as being Asabah. Thus, the property would be equally distributed among them; the share of a female is half the share of the male.
Allah knows best.