When does the waiting period ('iddah) begin for a wife whose husband has passed away if she was in the hospital after an accident, and is it permissible to postpone it?

The waiting period (iddah) for a widow begins on the date of her husband's death. Her stay in the hospital for treatment does not nullify it. Rather, the 'iddah and mourning period (ihdad) continue. She is excused in this situation and is not required to make up additional days. Her presence in the hospital does not affect her 'iddah.