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.
When a person distributes his property among his wife and daughters in his lifetime, then such a division is not called or considered division of inheritance. Rather, it is a gift (hibah). The division of inheritance takes place after the person’s death and not during his lifetime. There are two possible cases for what your cousin did:
Firstly, that he gave them his property while he is in sound health and not during a fatal illness that is likely to end in death; and the wife and daughters have accepted and taken possession of these properties and enjoyed full ownership and complete authority over them, being able to sell them or lease them out if they wish. In this case, when he passes away, his siblings have no share in these properties. However, if he divided his property with the intention of depriving his siblings of their shares in the inheritance, then he bears a sin for that according to the opinion of some scholars. Ibn Hajar Al-Haytami was once asked about a father who gave property to his sons with the sole intention of depriving his daughters of their shares in inheritance. He replied:
“If he made that division during illness leading to death, then it is considered a will made in favor of an heir. In this case, it should not be executed unless approved by the daughters; otherwise, it must be canceled. If he made that will during his sound health, then it is valid; and even if he intended to deprive some of his heirs, the will is still valid. The consequence in this case is that he bears a sin for doing that, but the division itself is not declared invalid because this has nothing to do with the way the gift has been granted...”
Some jurists held that such a person is not a sinner even if he intended to disinherit his daughters and bar them from their rightful inheritance as long as the will was made in a state of sound health. The Shaafiʻi scholar Ash-Shabraamallisi wrote in his Haashiyah ʻala Nihaayat Al-Muhtaaj, “If such a gift is made in a state of sound health, then it should be executed without restrictions and it does not involve any prohibition even if he intended to disinherit some of his heirs...”
The second case is that he has given them his properties as gifts during a fatal illness that is likely to end in death. In such a case, it is not a gift and is considered a will. Ibn Qudaamah wrote, “The religious rulings pertaining to gifts given during a person’s fatal illness that is likely to end in death are the same as those on wills...” [Al-Mughni]
As long as his wife and daughters are among his heirs, the will made in their favor cannot be executed unless approved by the other heirs (his siblings). A will made in favor of an heir must not be executed unless the other heirs give their consent to it. If he passes away, then his siblings are entitled to claim their due shares in the properties that he distributed during his lifetime.
As for your question about whether the deceased should give his brothers and sisters a share in his properties if he does not have a son, if you mean giving them some property as a gift during his lifetime, then you should know that he is not obliged to do so. However, if you are inquiring whether they are entitled to a share in his estate after his death, then you should know that the deceased’s siblings are entitled to inherit under two conditions: firstly, if the deceased’s father is not alive. Secondly, if the deceased has no male descendant, a son, a grandson, or a great-grandson, entitled to inherit.
If the deceased has no male descendant or a father (alive and entitled to inherit), the deceased’s siblings are entitled to inherit from him whether they are full siblings or half siblings from the father’s side.
As for the siblings from the mother’s side, they are entitled to inherit from him on one condition: that he has absolutely no descendant entitled to inherit, male or female, and has no parent entitled to inherit, a father, a grandfather, or a great-grandfather.
Allaah knows best.