What is the end date of the waiting period (iddah) for my paternal aunt, whose husband passed away on 14-4-2010, and is it calculated according to the Hijri date, given its difference in Libya?

The 'iddah (definition) (waiting period) for a pregnant widow ends upon delivery of her child. For a non-pregnant widow, her 'iddah is four months and ten days according to the Hijri calendar. If it is difficult to ascertain the beginning of the lunar months in your country, then she should refer to the nearest Muslim country. In this case: if Rabi' al-Akhir was incomplete, the 'iddah would end on the 8th of Ramadan (definition), and if it was complete, it would end on the 9th of Ramadan 1431 AH.