Salaam, I wanted to know that if My Father does the sacrifice of an animal. Does it mean I also would have to cut my hair and nails before Zil Hajj starts? Or only the person who is doing the sacrifice will have to follow this?
This ruling applies only to the one who is going to offer the sacrifice, namely the owner of the sacrificial animal.
Shaykh Ibn Baaz (may Allaah have mercy on him) said:
With regard to the family of the one who is going to offer the sacrifice, they are not subject to any obligations, and it is not forbidden for them to remove anything from their hair or nails, according to the sounder of the two scholarly views. Rather the ruling applies only to the one who is going to offer the sacrifice, the one who has bought the sacrificial animal from his own wealth. Fataawa Islamiyyah, 2/316.