If, during the lifetime of the father, one of his six married sons passes away, and then eight years later the father also passes away without leaving any will, do the children of the deceased son—i.e., the grandson and granddaughter—have any right to inherit from their grandfather’s estate according to Shariah?
It should be clarified that if a son or daughter passes away during the lifetime of his or her parents, then such a child does not inherit from the parents’ estate. Consequently, the heirs of that deceased child also do not acquire any right to claim a share in the parents’ inheritance through him or her. Therefore, in the present case, since the son passed away during the lifetime of his father, his children (the grandson and granddaughter) are not entitled to any share in their grandfather’s inheritance according to Shariah.
However, if all the remaining heirs are sane and mature, and they willingly choose—out of kindness and maintenance of family ties—to give something to the children of their deceased brother (i.e., the nephew and nieces), they are permitted to do so. Such giving will be regarded as a voluntary act of charity and kindness, and it will, without doubt, be a means of reward and provision for the Hereafter. Nonetheless, doing so is not legally obligatory upon them under Islamic law.
کما فی رد المحتار: وشروطه ثلاثة موت مورث حقيقة او حكما كمفقود او تقديرا كجنين فيه غرة ووجود وارثه عند موته حيا حقيقة او تقديرا كالحمل والعلم بجهة ارثه اھ (كتاب الفرائض ج 6 ص 757 ط ايچ ام سعید)
وفی المبسوط للسرخسی: وانما تحقق الوجوب له عند الموت ولان المانع صفة ولا يعرف ذلك الا عند الموت لان صفة الوراثة لا تكون الا بعد بقاء الوارث حيا بعد موت المورث اھ (باب الوصية للمورث الخ ج 27 ص 176 ط اسلامية)