Alsalam aalaykom,
My wife has got a 5 year old child from her previous marriage. She recently lost his custody and the child has been taken by his father in Egypt.
My wife took our baby and flew to Egypt and does not intend to come back to me before she gets back the custody (if she does get it at all!!)
She basically left a whole family for her 5 year old. What does Islam say about this?
Fi aman allah
Adam

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

If a woman remarries, she would lose her right to the custody of her child from her ex-husband and his custody will be transferred to the more deserving of his fostering after her according to the order stated by Muslim jurists as clarified in Fatwa 84618. However, the wife has to obey her husband in what is permissible, and she is not allowed to leave his house or travel without his permission. Thus, if your wife traveled to Egypt without your permission, insisting to stay there against your wish and not to return until she gets back her daughter, then she is sinful and neglectful about the rights of her husband and she is considered a disobedient wife.

Anyway, we advise you to contact her and remind her of Allaah The Almighty and obedience to her husband that Allaah has made obligatory upon her. If she takes heed and returns to her house, this will be fine, otherwise you may seek the help of the wise people from among your relatives and hers to reconcile between both of you. Allaah The Almighty Says (what means): {And if you fear dissension between the two, send an arbitrator from his people and an arbitrator from her people. If they both desire reconciliation, Allaah Will Cause it between them.}[Quran 4:35] If reconciliation did not take place, it might be preferable to divorce her, because there is no good for a man to stay with a woman who disregards his guardianship and whose rebellion has reached a stage in which she traveled to a country that her husband does not want her to travel to or stay in.