What is the ruling on a woman in 'iddah (mourning period) staying with her daughter who is in nifas (postpartum bleeding) for more than two weeks?

The wife must immediately return to the marital home to spend the night there, as this is a right of the husband. This is indicated by the story of Furay'ah bint Malik, whom the Messenger of Allah, peace and blessings be upon him, commanded to stay in her home until her 'iddah (waiting period) was over, which 'Uthman ibn 'Affan, may Allah be pleased with him, used as an evidence. She must repent and seek forgiveness for her shortcomings.