The Muslim Son Does Not Inherit From the Property of a Disbelieving Father

Question :

If a father used to strictly observe the five prayers and the pillars of Islam, but he considered it permissible to make vows and slaughter animals for the inhabitants of tombs and mausoleums, may his son take anything from his wealth by which he may build his future, or may he inherit from him or not?

Answer:

Any legally capable person among the Muslims who believed that it is permissible to make vows and slaughter for the inhabitants of the graves (should know that) this belief of his is Shirk which takes him out of the fold of Islam. Such person must be called to repent for three days and relations with him must be severed: If he does so, (all well and good), but if not, he should be killed.

As for the son taking from his father what he requires to build his future, and (as regards) his being his heir after his death in the same question which was asked, that is based upon knowledge of the true position of the father and his situation at the time of his death: If his father died upon these beliefs and it is not known that he turned to Allah in repentance, then he may not inherit from him, according to the words of the Prophet :
"The Muslim does not inherit the disbeliever, neither does the disbeliever inherit the Muslim."

And it is permissible for the son to accept whatever his father gave willingly from his wealth while he is alive.

Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 5 Page 81