A non-Muslim son embracing Islam before the division of his father's inheritance
4-7-2010 | IslamWeb
Question:
As-salam `alaykum wa rahmat ALLAH
In view of the hadeeth that "The believer does not inherit from a kaafir (disbeliever) and the kaafir does not inherit from a believer", what si the ruling if the situation is as follows:
a muslim father dies leaving behind his children among whom one grows as a kaafir,upon the death of his father he accepts islam(whether faithfully or due to his wealth), should he be among the heirs? Also if it happens otherwise whereby a son accepts islam and his father dies, does he still have right over his father property(i.e inherit)?
Jazakum ALLAH khaira.
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
The majority of the scholars are of the view that a non-Muslim does not inherit his Muslim relative even if he becomes a Muslim (after the death of the inherited person) before the division of the inheritance as the Prophet said: “…And a non-Muslim does not inherit a Muslim.” [Muslim] Ibn Qudaamah stated that this is the view of Abu Haneefah, Maalik, Ash-Shaafi’i, and the view of the majority of the jurists and one of the two narrations from Ahmad, and this is also the view chosen by Ibn ‘Uthaymeen 
.
However, a group of scholars are of the view that if a non-Muslim embraces Islam before the division of the inheritance of his Muslim relative (even after the death of the inherited person), then he inherits whether he was in principle a non-Muslim or that he was an apostate, and this is the view of the Hanbali School and Ibn Al-Qayyim prefers this view and he considered it to be one of the beauties of the Sharee’ah (Islamic law).
To conclude, there is a controversy about this issue and the statement that he [a non-Muslim who embraces Islam] will inherit is not unlikely as it is confirmed that ‘Uthmaan 
made a man who embraced Islam before the division of the inheritance inherit from that inheritance, and the same thing is reported from ‘Umar that he decreed that if someone becomes a Muslim before the division of inheritance, then he has his share from inheritance.
As regards if the son becomes a Muslim before the death of his Muslim father, then he inherits him and we do not know any difference of opinion in this regard because what should be taken into account is being of the same religion or of different religions at the time of death.
Allaah Knows best.