My wife's father is around 80 years old, he has two daughters and three sons. He is still alive and all his children are married. Around thirty years ago, he purchased three land plots on his sons' names (and gave them the possession). He purchased these lands when all the children were still unmarried, and at that time, all of them were still in school. He also purchased some more properties that he also gave to his sons, and he also had a business, which he also handed over to his sons. Besides that, he made a will (and showed it to his sons) in which he mentioned the share of his sons regarding the remaining properties which are still on his name apart from the properties that he purchased on their names. His wife (my wife's mother died one year back) had some properties on her name; he is dividing these properties (which are on his wife's name) among the children. He became sick and still does not want to give his daughters their share and declared that they will get their share only after his death. 1) Can a person purchase property on his sons' name only and ignore the daughters when all the children are still going to school and are unmarried 2) Can he give his property to his sons during his lifetime and tell his daughters that they will get their share after his death. 3) He always lied to his daughters about the properties and ignored the rights of his daughters; he hid some properties, which were purchased on his sons' names, from his daughters.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger. 

We will answer your question in the following points:

Firstly, the fact that the father registered the property in the name of his sons is not considered a full transfer of ownership unless they actually take the property in their possession before his death and are free to dispose of it as they wish. This action is usually intended to be a bequest so that they would own the property after his death apart from the other heirs. Such a bequest is not acknowledged in Islamic law because it is a bequest made to an heir. It should not be executed unless all the heirs agree to it. The Prophet, sallallaahu ʻalayhi wa sallam, said, “Allaah has appointed for everyone his rightful share, so no bequest is to be made to an heir.” [At-Tirmithi] The version cited by Ad-Daaraqutni reads, “... unless approved by the heirs.” Al-Haafith Ibn Hajar stated that its chain of narration is hasan (good) in his book Buloogh Al-Maraam.

Secondly, it is impermissible for the father to offer some of his properties as gifts to his sons without giving the same to his daughters. According to the preponderant scholarly view, it is incumbent on him to offer all his children equal gifts. It has been authentically reported that Basheer ibn Sa'd offered his son An-Nuʻmaan a gift. He came to the Prophet, sallallaahu ʻalayhi wa sallam, to ask him to bear witness to that. The Prophet, sallallaahu ʻalayhi wa sallam, asked, “O Basheer, do you have any other children besides this one?” He said, “Yes.” The Messenger of Allaah, sallallaahu ʻalayhi wa sallam, said, “Have you given all of them a gift like that which you have given to this son of yours?” He said, “No.” The Messenger of Allaah, sallallaahu ʻalayhi wa sallam, said, “Then do not ask me to bear witness; I will not bear witness to unfairness.” [Al-Bukhari and Muslim] Another version cited by Imaam Ahmad reads, “Basheer took his gift back.” The wording cited in Saheeh Muslim reads, “Thereupon he said, ' Fear Allaah, and treat you children fairly.' My father returned and got back the gift.”

A version cited by Imaam Ahmad reads, “Your children have a right over you; that you be just to them.”

Hence, your wife's father is obliged to observe equality and justice among his children and to offer them all equal gifts or take back the gift that he had offered to his sons while denying his daughters in case the gift has been accepted and taken into possession by the sons. If it is a bequest, then he must cancel it because it is prohibited, as was mentioned above.

Thirdly, the property of the late mother of your wife should be distributed among her rightful heirs according to the sharee'ah laws, including both her daughters and sons. The father has no right to deny any of the eligible heirs their shares in the estate.

This is the general religious ruling in this regard; you are advised to consult local scholars directly to seek a more detailed account on the religious ruling without asking about hypothetical situations that do not actually exist.

Allaah knows best.