What is the ruling regarding a wife apostatizing from Islam and converting to Christianity, and to whom does the custody of minor children go in this case?

If the wife's apostasy is confirmed, she must be advised and warned about the danger of apostasy. If she repents, she remains under your marital bond. Otherwise, a new marriage contract is required after her 'iddah (definition) (waiting period). If she insists on her disbelief, she has no right to custody of the children due to the absence of the condition of Islam. You must then strive to take the children from her. We also warn against the danger of a Muslim residing among polytheists.