Is it necessary to repeat the Hajj, or only the Tawaf Al-Ifadah, on behalf of a father who passed away after returning to his country and before completing the Tawaf Al-Ifadah?

If your father passed away without completing the circumambulation of Ifadah (Tawaf (definition) al-Ifadah), which is a pillar of Hajj, then he is considered to have died in a state of ihram (definition). The preponderant opinion is that the ritual is not completed on his behalf, based on the Prophet's (peace be upon him) statement concerning one who dies in a state of ihram: "Wash him with water and sidr, and shroud him in his two garments, and do not cover his head, for Allah will resurrect him on the Day of Resurrection, reciting the talbiyah (definition)."

However, if the circumambulation he did not complete was the Farewell Circumambulation (Tawaf al-Wada'), then his Hajj is valid, but a sacrifice (dam) is due for leaving the Farewell Circumambulation, as it is obligatory according to the preponderant opinion of scholars. Therefore, you must slaughter a sacrifice in the Haram (definition) and distribute it among the poor.