Book of Apostasy
Apostasy is the severance of one’s Islam through an intention, a statement of unbelief, or an act—whether it is done in mockery, obstinacy, or conviction. Thus, whoever denies the Creator or the messengers, belies any messenger, declares lawful anything unanimously forbidden—such as unlawful sexual intercourse—or the reverse, denies an obligation established by consensus—or the reverse—resolves to disbelieve tomorrow, or even hesitates about disbelief, has become an unbeliever. Among the acts that entail disbelief is any deliberate deed that openly mocks the religion or rejects it—such as casting a Qur’an into filth, or prostrating to an idol or to the sun.

The apostasy of a minor, an insane person, or one acting under duress is not valid. If someone apostatises and then goes mad, he is not executed while insane. The relied-upon view is that the apostasy of an intoxicated person is valid, as is his return to Islam. Testimony to a person’s apostasy is accepted without qualification, though another view requires detail. On the first position, if witnesses testify that he apostatised and he denies it, judgment is rendered on their testimony. If he pleads, “I was coerced,” and there is a corroborating indication—such as his being a prisoner of unbelievers—he is believed upon oath; otherwise, he is not. When the witnesses merely declare, “He uttered a word of disbelief,” and he then asserts coercion, he is believed unconditionally.

If a man known to be Muslim dies leaving two Muslim sons, and one son claims, “He apostatised and died an unbeliever,” then—if he specifies the cause of the father’s disbelief—that son does not inherit and his share reverts to the public treasury; the same ruling, on the stronger opinion, applies even if he makes the allegation without specifying a cause.

Both the male and female apostate must be called to repent (istitabah); another view holds that this is merely recommended. According to one opinion it is to be done immediately, while another allows three days. If they persist, they are executed; if they embrace Islam, it is accepted and they are left unharmed. Some maintain that his return to Islam is not accepted if he had apostatised to a covert form of unbelief, such as that of the zindiqs or the Bāṭinis.

As for the child of an apostate, whether conceived before or after the apostasy: if either parent is Muslim, the child is Muslim; if both parents are apostates, the child is still deemed Muslim—though one opinion holds he follows their apostasy, and another that he is an original unbeliever.

I say: the stronger view is that he is an apostate, and the Iraqi scholars report consensus on his disbelief. Allah knows best.