Is zakat obligatory on money saved by the deceased, knowing that it reached the nisab, but it is not known whether a full year has passed over it?

Zakat becomes obligatory on the deceased's saved wealth if they died after Zakat became due on them but before it was paid. It should be disbursed from their estate before distribution. If the deposit dates can be ascertained and it becomes clear that the funds reached the Nisab (minimum threshold) and a full year passed over them at the time of the father's death, then Zakat is obligatory in this case. However, if it is impossible to determine the date of saving, or if there is doubt about the funds reaching the Nisab and a full year passing over them, then Zakat is not obligatory, because the fundamental principle is the acquittal of one's liability.