They ask you about the inheritance of a person who is survived by neither ascendants nor descendants. If one dies and leaves no children, and he had a sister, she gets half the inheritance. If she dies first, he inherits from her if she left no children. If there were two sisters they get two-thirds of the inheritance, if there are sisters and brothers, the brother would get twice the share of the sister for reasons already explained (2:80), (4:11). Allah clarifies the Laws so that you might not go astray. Allah is the Knower of all things.