When does a woman's iddah end if her father passed away on October 15, 2023, after Maghrib prayer, and she immediately intended to observe the iddah?

The waiting period (iddah) for a pregnant woman ends with the delivery of her entire pregnancy, based on the Almighty’s saying: ﴿And for those who are pregnant, their term is until they deliver their burden.﴾ If she is not pregnant, her waiting period is four months and ten days, based on the Almighty’s saying: ﴿And those among you who die and leave wives behind, they shall wait on their souls for four months and ten [days].﴾ The waiting period begins from the time of death and is calculated by lunar months, not Gregorian. So, if the husband passed away on October 15, 2023, after sunset, corresponding to the 1st of Rabi’ al-Thani 1445 AH, then the waiting period ends on the tenth day of Sha’ban.