Islamic Inheritance & the Non-Muslim. Usama b. Zaid reported Allah's Messenger as saying: A Muslim is not entitled to inherit from a non-Muslim, & a non-Muslim is not entitled to inherit from a Muslim. [Sahih Muslim 3928]. This has notable conse-quences

Though in Islam a Muslim woman is not permitted to marry a non-Muslim, a Muslim man can marry outside the faith.  So if a Muslim orphan marries a Christian lady, has two children with her who both become Christian, and then dies before his wife & children do, Muhammad's declaration above would mean that no one in his family would inherit any of his wealth! To be sure, in Islam non-Muslims are "the worst of creatures" (Quran 98:6), but nonetheless should the children still not receive anything at all from their father?
Say instead that in our example both children had become Muslim and that the Christian wife died first.  What Muhammad has decreed would mean that neither the father nor the children would inherit anything as a result of the wife's death.  Is this the best result? 
Finally, consider the case of a Muslim individual with no other family members alive, and who wishes to leave his entire fortune to charity.  Does Muhammad's decree compel this individual to seek to bequeath his fortune to charities that only benefit Muslims?