There are a number of contradictions or mathematical problems in the inheritance shares that are specified in the Qur'an, cf. It just doesn't add up!
Interestingly, Ali inherited from Abu Talib, uncle of Muhammad, who died a pagan (Sahih Bukhari 5.579).
Narrated Jabir:
Allah's Apostle came to visit me while I was sick and unconscious. He performed ablution and sprinkled the remaining water on me and I became conscious and said, "O Allah's Apostle! To whom will my inheritance go as I have neither ascendants nor descendants?" Then the Divine verses regarding Fara'id (inheritance) were revealed. (Sahih Bukhari 1.193)