A bequest that contradicts the Islamic law is not to be executed
26-7-2014 | IslamWeb
Question:
Assalaamu ‘Alaykum; Please calculate the inheritance according to the following information -Does the deceased have male relatives who are entitled to inherit: (A son) Number 1 -Does the deceased have female relatives who are entitled to inherit : (A daughter) Number 1 - The will which the deceased left behind and that is related to his inheritance is : The son is from the deceased first wife and the daughter is from the second wife. The deceased made a will not according to Sharia law. In the will it said excluding the son from properties the deceased had. But he had 2 plots which he didn't mention in the will and every one knew it was for the son the deceased second wife has also died leaving all the assets to her only daughter who is 14 years old, but the son from the first wife is 27 years old. What shd the son inherit. The deceased used to always take care of the son he was sending him every month.
Answer:
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 
is His slave and messenger.
No consideration is to be given to the deceased's instruction to exclude his son from the inheritance; the instruction of Allaah should be put into effect instead. Allaah says (what means): {Allaah instructs you concerning your children [i.e. their portions of inheritance]: for the male, what is equal to the share of two females.}[Quran 4:11]
Hence, the son inherits from the entire estate left by his father without any exception. The fact that the son is from one wife and the daughter is from another wife does not affect the inheritance as both of them are children of the deceased and he is their father, and they both inherit from him based on lineage.
Therefore, if the deceased did not leave any other heirs except those mentioned in the question, then the inheritance should be divided between the son and the daughter by Ta’seeb (by virtue of having a paternal relation with the deceased and not having an allotted share, so they get what is left after the allotted shares have been distributed); the male is entitled to a share two times that of the female, as per the above verse.
Hence, the entire inheritance should be divided into 3 shares, the son gets 2 shares and the daughter gets 1 share.
Finally, it should be noted, dear sister, that the issue of inheritance is very complex, so a mere Fatwa, which is an answer issued according to the question, is not enough. Rather, the matter should be referred to an Islamic court to look into the case and investigate, as there may be an heir who would not be known except after investigation, and there might also be a will, debts, or other dues that are not known to the heirs. It is known that these rights take priority to the right of the heirs in the inheritance. Therefore, the inheritance should not be divided without resorting to an Islamic court, if any, in order to fulfill the interests of both the living and the dead.
Allaah Knows best.