What is the share of the heirs (full brother, full sister) from the inheritance of the deceased "Khalifa," considering the existence of a will stating "all his possessions belong to H.W.T," which was written during his death illness from which he died, and remained secret without the consent of the heirs?

If the deceased bequeathed all his estate to his two nephews (his wife’s sister’s sons), and the testator had two brothers, one of whom was the father of the two beneficiaries, and then he died, leaving a full brother and a full sister, then the will is not proven merely by the claim of the testator’s wife; rather, it requires witnesses. Jurists differed on the number of witnesses required to prove a will. Some said it is proven by one man and two women, or one man and an oath, while others said it is not proven except by two men.

If the will is not proven and the heirs do not confirm it, then the two nephews receive nothing, and the estate goes to the heirs (the full brother and full sister). The estate is divided into three shares: the brother receives two shares, and the sister receives one share.

However, if the will is proven by testimony or by the heirs' acknowledgment, then the two nephews are entitled to only one-third of the estate, not all of it, unless the heirs permit more than the one-third. This is based on the Hadith (definition) of Sa’d ibn Abi Waqqas: "One-third, and one-third is much." So, the two nephews take one-third, and the remaining two-thirds are divided between the full brother and the full sister.