I performed Hajj on behalf of my father, and I did the tawaf of ifadah, but I did not do the sa'y. Should I perform the sa'y on his behalf during these days, and is the Hajj valid?

Question:
I performed Hajj on behalf of my father six years ago as an ifrad Hajj, and I did the tawaf of ifadah, but I did not do the sa'y because I did not know. Now that I know, should I perform the sa'y during these days? Is there a sin on me? Is the Hajj valid? May Allah reward you with good, and may He do you good.

Answer:
The Hajj is valid, but it is not complete; the sa'y remains. You must return and perform the sa'y. If you had intercourse during this period, you must also pay the fidyah, which is slaughtering a sheep that is acceptable for the udhiyah. You slaughter it in Makkah and distribute it to the poor of the Haram. If you cannot find one, you fast for ten days. If you did not have intercourse, it is sufficient for you to return and perform the sa'y for the part you left.