The ruling on one who denies the Reckoning and the punishment in the grave

Question:
He says: Honorable Shaykh, may Allah grant you success, I have a relative who is over seventy years old, and he is of sound mind. He performs all the obligatory acts, foremost among them the prayer, and he prays in the mosque with the congregation. However, he believes that when he dies, everything ends, meaning that there is no Reckoning, no punishment, and no recompense in the grave or after it. We tried to clarify the matter to him, explaining that there is a questioning by the two angels in the grave, and that there is a Resurrection and a Reckoning, but he strongly rejects this. The question, may Allah grant you success, is: Is this man excused due to ignorance, despite our having clarified these matters to him?

Answer:
This has two cases. The first case is if his mind is disturbed and there is a deficiency in it, and he holds these views due to a disorder in his mind; in that case, he is not held accountable, if Allah wills. But if his mind is sound and he says this seriously, this is disbelief. This is major shirk (associating partners with Allah) that takes one out of the religion, and he has no excuse, because the proof has reached him. He reads the Qur'an and hears the words of the scholars regarding the Day of Resurrection and its details. Yes.