Died leaving a wife, 2 daughters and 2 full sisters
17-7-2014 | IslamWeb
Question:
Assalaamu ‘Alaykum; Please calculate the inheritance according to the following information -Does the deceased have female relatives who are entitled to inherit : (A daughter) Number 2 (A wife) Number 1 (A full sister) Number 2 - The will which the deceased left behind and that is related to his inheritance is : The will says everything goes to my wife after my death, and then to my daughters after the death of my wife.
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, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
This bequest in question is a bequest made in favor of an heir. It is not binding as per the Sharee'ah and should not be executed except with the consent of the other heirs – including the two full sisters. The Prophet, sallallaahu ‘alayhi wa sallam, said: “Allaah has appointed for everyone who has a right what is due to him, and no bequest must be made in favor an heir.” [Abu Daawood, An-Nasaa'i, At-Tirmithi, Ibn Maajah, and Ad-Daaraqutni] Ad-Daaraqutni 
reported the Hadeeth with a different wording which adds, “... except with the consent of the other heirs.”
The heirs who refuse to accept such a bequest are entitled to their due share of the inheritance and their shares should not be decreased because of the bequest.
If the deceased did not leave heirs entitled to inherit other than those mentioned in the question, then the wife gets one-eighth of the estate as a prescribed share because the deceased has descendants entitled to inherit. Allaah, The Exalted, says (what means): {...but if you leave a child, then for them [i.e. the wives] is an eighth of what you leave, after any bequest you [may have] made or debt...}[Quran 4:12]
The two daughters get two-thirds as a fixed share. The Prophet, sallallaahu ‘alayhi wa sallam, gave the two daughters of Sa’d ibn Ar-Rabee’ two-thirds of his estate. [Ahmad, Abu Daawood and At-Tirmithi] Ibn Al-Munthir said: “The scholars have unanimously agreed that two daughters get two-thirds.”
The remainder of the estate is to be divided equally among the two full sisters by virtue of Ta‘seeb (i.e. 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) as it is confirmed that the Prophet, sallallaahu ‘alayhi wa sallam, gave the (full) sister the remainder of the inheritance after the share of the daughter and the son's daughter. The Hadeeth was narrated on the authority of Huzayl ibn Shurahbeel and reported by Al-Bukhari. It is for this reason that the scholars included the (full) sister among the heirs who inherit by Ta‘seeb if the deceased's descendants are females. In this case, she takes whatever remains of the inheritance after its division as stated in Ar-Rahabiyyah (Poem on Islamic Laws of Inheritance).
Hence, the estate should be divided into 48 shares; the wife gets one-eighth of them (i.e. six shares), the two daughters get two-thirds (i.e. 32 shares: 16 shares each), and the rest (i.e. ten shares) should be given to the two full sisters; each gets five shares.
Allaah Knows best.