What is the ruling of Islamic law regarding a man who verbally divorced his fourth wife, then married a fifth wife عرفيًا (customarily/non-officially), while the official divorce papers for the fourth wife have not yet been issued, and then he exploited his ex-wife's name to register his children from his fifth wife, and he threatens his ex-wife with taking their daughter away from her when she demands her official papers?

If a man divorces one of his four wives and marries another before the iddah (waiting period) of the divorced wife ends, then his marriage is invalid. However, if the divorce was irrevocable (talaq bain), then it is valid according to the Maliki and Shafi'i schools of thought.

If a man attributes his children from one woman to another, this is void, and it is obligatory to correct the lineage of the children to their biological mother.

It is not permissible for him to prevent his divorced wife from the custody of her daughter without right, nor should he withhold her divorce document; otherwise, he would be an oppressor. The one who arbitrates these disputes is the Sharia judge.