Is it Islamically permissible for a father to register all his property to his only son, thereby depriving his daughter of inheritance? And is it permissible for the son to keep it, or must it be distributed according to Islamic law?

A father dedicating his property to his male children with the intention of depriving his daughters of inheritance is a clear injustice and a vivid example of the pre-Islamic era (Jahiliyyah) that denied women inheritance. Islam came to establish a woman's lawful share, as stated in the Almighty's words: (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 – a legal share).

If the transfer of property to sons without daughters is a will, then it is a will to an heir, which is not enforceable unless the other heirs agree. If it is a gift, then it is nullified by a group of scholars if it is not equitable, especially if it was done during a death illness and the sons did not take possession of it during the father's lifetime; it is to be returned after his death.