A:
If the reality is as you mentioned in the question, which is that your father died before the elapse of a Hawl, there is no Zakah due on him, since he died before the elapse of a full Hawl on his property.
Each heir should pay the Zakah due on their share of the inheritance if it reaches the Nisab or more, whether by itself or when added to other money or commercial commodities and a Hawl passes since the death of the testator. The rate of Zakah that must be paid is 2.5%.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.