How can one deal with a wife who is grieving over her son from a previous marriage, who was raised in a corrupt environment, to help her overcome this crisis, especially with the imminent birth of their shared child?

Advise the woman who does not love her son to pray for him frequently, for the prayers of parents are answered, as stated in the Hadith: "Three supplications are answered without a doubt: the supplication of a parent against his child, the supplication of the traveler, and the supplication of the oppressed." And that she should be diligent in the prescribed remembrances (adhkar), especially the supplication before intimacy: "In the name of Allah. O Allah, keep Satan away from us, and keep Satan away from what You رزقنا (provide for) us. For if a child is destined between them from that, Satan will never harm him." And that she should bear her motherhood for him, for perhaps Allah will guide him or bless her with another child.