The Sons of a Mushrik Who Affirm Allah's Oneness May not Inherit from him

Question :

A man prays and fasts and performs all of the pillars of Islam, but in spite of all this, he supplicates to other than Allah, by making Tawassul through Walis, he seeks help from them, and believes that they are able to bring him. benefits and protect him from harm. Inform us - may Allah reward you with goodness may his sons who affirm the Oneness of Allah and do not associate any partners with Allah inherit from him? Also what is the ruling on them?

Answer:

Whoever prayed, fasted and performed the pillars of Islam, except that he seeks help from the dead and the absent living and the angels and the like, is a Mushrik and if he was advised, but he did not accept (the advice) and remained determined upon this until his death, he is a Mushrik, guilty of major Shirk, which takes him out of the fold of Islam. So he should not be washed, nor should the funeral prayer be prayed over him, nor should he be buried in the graveyard of the Muslims, nor should prayer for forgiveness be made for him, nor should his sons, nor his father, nor his brothers nor any other Muslim who affirms the Oneness of Allah inherit from him, due to the difference in their religion, based upon the saying of the Prophet:
"The Muslim does not inherit the disbeliever, neither does the disbeliever inherit the Muslim."

And may peace and blessings be upon our Prophet, Muhammad and upon his family and Companions.

Source:
Fatawa Islamiyah, Vol. 5 Page 82