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 is His slave and Messenger.
According to the most preponderant opinion of the scholars the congregational prayer is an obligation for whoever hears the call, as clarified in Fatwa 82538.
If someone's parents (or one of them) orders him to do something for them while the Iqaamah (establishment of prayer) is called, and he is able to do what is asked of him and then attend the prayer, then he has to obey them because it is an obligation on him to obey his parents as this does not lead to neglecting another obligation, even if his father orders him to delay the prayer so that they could perform it together at home.
However, if he knows that by following their order he will miss the congregational prayer, and he will not be able to pray in congregation at all, then he has to put in priority the congregational prayer and once he prays, he will do what he is ordered. He should apologize nicely to them as they have a great right on him, and should promise them to do what they ordered him after the prayer.
As regards the Hadeeth which reads: "If I found my parents, or one of them and 'Ishaa' prayer is called and my mother calls me: "O Muhammad!" I would have answered her: "Yes, here I am, my mother. [and I wouldn't have gone for the prayer]", it is a weak Hadeeth which is reported by Al-Bayhaqi .
Allaah Knows best.