In the first place, we would like to stress that interfaith inheritance is forbidden because difference in religion is among the reasons that inhibit inheritance. It is reported on the authority of Usamah bin Zayd (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) says: “Neither a Muslim should inherit a non-Muslim, nor should a non-Muslim inherit a Muslim.” (Reported by Al-Bukhari, Abu-Dawud, At-Timidhi and Ibn Majah)
Also, `Abdullah bin `Amru (may Allah be pleased with him) reports that the Prophet (peace and blessings be upon him) says: “There is no interfaith inheritance.” (Reported by Ahmed, Abu Dawud and Ibn Majah)
Imam Ash-Shawkani states that: “These Hadiths indicate that a Muslim is not allowed to inherit from a non-Muslim, and vice versa, as agreed by the consensus of Muslim scholars. But, the issue of people who apostatize is still controversial.”
Sheikh Ahmad Haridi, former Mufti of Egypt, says: “It is well established in Islam that difference in religion between a Muslim and his relatives or spouse makes inheritance inhibited among them. Thus, a Muslim neither inherits from nor bequeaths to non-Muslims, whether Christians, Jews or polytheists. This is the opinion agreed upon among the majority of Muslim scholars of the Companions and their successors up to contemporary ones.”
Mu`adh, Mu`awiah, Ibn Al-Musayyeb, Masruq and Al-Nakh`ie were cited as holding the view that a Muslim may inherit a non-Muslim, but not vice versa. In the same way, a Muslim man may marry a woman from among the People of the Book, while a non-Muslim man cannot marry a Muslim woman.
Finally, we can say, “in view of the aforementioned Hadiths as well as the opinions of well-versed jurists, interfaith inheritance (between Islam and other religions) is not allowed.