A. al-Zuhayli said in al-Fiqh al-islami wa adillatuh (Islamic Law and Its Proof-Texts 8:263): "All four schools agree that difference in Religion between legator and inheritor, one being Muslim and the other not, precludes inheritance. The Muslim cannot leave anything to the non-Muslim nor the non-Muslim to the Muslim, whether through parenthood or marriage, due to the Prophet's sayings: "The Muslim does not leave anything to the non-Muslim nor the non-Muslim to the Muslim" [narrated by Bukhari and Muslim], and "The people of two different religious communities inherit nothing from each other" [narrated by Tirmidhi, Ahmad, Abu Dawud, and Ibn Majah; Darimi narrates the same also from `Umar]. This is what applies because patronage (wilaya) is severed between the Muslim and the non-Muslim. Egyptian law and Syrian law stipulate: "There is no mutual inheritance between Muslim and non-Muslim."
al-Zuhayli continues: "Mu`adh ibn Jabal, Mu`awiya, Ibn al-Hanafiyya, Muhammad ibn `Ali ibn al-Husayn, and Masruq -- may Allah be well pleased with them -- held the view that the Muslim may inherit from the non-Muslim but not the opposite, based on the Prophet's hadith al-islam ya`lu wa la yu`la "Islam dominates and is not dominated" [a fair (hasan) hadith narrated by al-Rawyani, al-Daraqutni, al-Bayhaqi, and al-Diya' from `A'idh ibn `Amr].... and Ahmad said: "The Muslim inherits from his non-Muslim manumitted slave" due to the general meaning of the hadith al-wala' li man a`taq: "The rights of patronage belong to the manumitter" [narrated by Bukhari and Muslim]." End of Zuhayli's text.
The Mufti of Egypt Muhammad Hasanayn Makhluf was asked a question to which he gave this answer in his Fatawa shar`iyya (2:233-234):
Answer: "The inheritance of this deceased Muslim all goes to his Muslim wife. There is no inheritance for the children he left behind as mentioned above, due to their embrace of the Christian religion at the time of his death and the fact that none of them followed him in accepting Islam. Difference in religion precludes inheritance, as stipulated by the jurisprudents, and Allah knows best."