Is the waiting period (iddah) waived for an elderly woman who is unable to care for herself, and is it permissible for her to move between her sons' and daughters' homes to observe the waiting period?

A woman whose husband has died must observe her 'iddah (waiting period) in the house where her husband died while she was in it. She is not permitted to abandon the 'iddah due to old age. She may go out during the day for a need, and at any time if there is a necessity.

If she is ill, her children should take turns caring for her, or she can hire someone to nurse her. If she is unable to do any of that and is forced to go to one of her children's homes for care, then there is no blame upon her for that, to the extent of the necessity.