A widow in her `Iddah moving to another house out of necessity

Q: My brother-in-law died in Riyadh. My sister had a separate house of her own, and her neighbors were her husband's children from another wife. Out of fear for her, I told my mother to stay with her until her `Iddah (woman's prescribed waiting period after widowhood) would come to an end, and my mother, may Allah reward her, (Part No. 20; Page No. 473) agreed. She stayed with my sister for three months and four days. Then, I had a phone call telling me that my father was very sick, and I had to take him to Tabuk for treatment, as there was no one else to accompany him to the hospital. I felt worried for my mother and sister if I left them to take my father to hospital and they also felt afraid. I discussed the matter with my mother in Riyadh and she asked me for my opinion. I told her that they had better go immediately to our house in Al-Dirah to stay with my elder sister and her husband, and call me after their arrival so that I could come and take my father to Tabuk for treatment. Are we considered sinful, as we made my sister leave her house before the end of her `Iddah, even though we know the rulings on the `Iddah prescribed for death?

A: If your widowed sister moves to a house other than her husband's during her `Iddah out of necessity, such as fear of staying alone there and not being safe, there is no harm in this. She may continue her `Iddah in the house she moves to. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.