Is it permissible for a widow to observe her iddah (waiting period) in the house of her husband's family or her own family, if it is difficult for her to spend the nights in her own home due to war conditions and fuel scarcity?

A woman observing the 'iddah (waiting period) after her husband's death must remain in the home where her husband died. She is not permitted to move to a mourning house or any other house for overnight stay, as long as she can stay in her husband's home without harm.