My father performed Hajj in the early 1980s i.e. nearly twenty-seven years ago. Having acted in throwing the pebbles upon what he understood from Allaah’s saying (what means): {Then whoever hastens [his departure] in two days – there is no sin upon him} [Quran 2:203], he threw the pebbles on the first and second days of 'Eid rather than on the first and second days of Tashreeq. What is due on him now that he came to know that the two days mentioned in the verse are the second and third days (of 'Eid)?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

If your father, as is mentioned in the question, did neither throw the pebbles on the second day of Tashreeq, nor spend the night prior to it at Mina, then a sacrifice is due on him: i.e. a sheep is to be slaughtered in the Sanctuary and its flesh is to be distributed among the poor therein, because he did not throw the pebbles on the second day of Tashreeq. A mudd (750ml) of foodstuff is also due on him for the poor inhabitants of the Sanctuary because he did not spend the twelfth night of Thul-Hijjah at Mina. We hope that there would be no sin on him because he was ignorant of the Sharee'ah ruling.

Allaah Knows best.