What is the ruling of Islamic law regarding the failure of the mother and sister to execute the deceased father's will concerning the sister's relinquishment of the apartment to her younger brother upon his marriage?

If the father gave the apartment to his daughter for dwelling only, on condition that she gives it to her brother upon his marriage, then the apartment is considered part of the inheritance after the father's death and is to be divided according to the Islamic law among all heirs. Neither the daughter nor the son has exclusive rights to it. The deceased's wife does not have the right to prevent any heir from their share or to dispose of the apartment. The inheritance must be divided in accordance with Islamic law, and in case of dispute, the matter should be referred to the Sharia court or presented to scholars.