What should a man do who divorced his Jewish wife and has a son with her, while she is holding onto the son and has not converted to Islam, and he resides in the West Bank?

The custody of the child, according to the majority of scholars, does not belong to the woman. The father should use permissible means that do not harm the father or the child to raise the latter and teach him the rulings of his religion. If this is not possible, then he must look after him and teach him. This is one of the drawbacks of marrying women of the People of the Book nowadays.