Who inherits a man who died without sons, but has nieces (daughters of his sister) and grandchildren from his nephew (son of his sister), and how is the inheritance distributed?

Nieces are considered among the uterine kin (dhawu al-arham) and inherit if there are no primary heirs (ashab al-furud) or agnates (asabah). This is the view of the Hanafis, Imam Ahmad, and the later Maliki and Shafi'i scholars. The existing uterine kin inherit the share of the person through whom they are connected. In this case, the nieces would be considered in the position of the sister and would receive half, then the remainder of the inheritance would be returned to them due to the absence of other heirs. The children of the nephew (son of the sister) receive nothing because the closer uterine kin excludes the more distant one. Therefore, the entire inheritance belongs to the nieces and is divided equally among them. If he were to bequeath to the children of his nephew a sum not exceeding one-third, that would be good.