Is zakat due for two years prior to the distribution of the inheritance, given that the deceased was unable to dispose of the money during those two years?

The obligatory zakat on your father's wealth, which he did not pay, must be disbursed. This is based on the verse: "after any bequest he may have made or debt" (An-Nisa: 11). The executor, heir, or ruler must disburse all obligations due from the deceased's estate after his death, even if he did not make a will concerning them. These obligations include debts, Hajj, zakat, vows, and expiations.