Must the family pay the full amount to the tailor after the death of the owner of the abaya, knowing that the abaya was not received?

If the fabric is yours and the tailoring is done by the tailor, then the lease (ijarah) is not nullified by the death of either party. The heirs are obligated to pay the wages from the inheritance and receive the abaya. If you bought the fabric from the shop and stipulated its tailoring, then this is a permissible and binding sale with a condition for both parties, and it is not nullified by death. If the fabric and the work are from the tailor as a single transaction (istisna' contract), then the tailor is obligated to complete the abaya, and the heirs are obligated to pay the remaining price from the inheritance, unless both parties agree to nullify the contract.