Should one interrupt the prayer upon hearing a parent's call and then resume it later?

If one of the parents calls their child while he is praying, then in an obligatory prayer, it is not permissible to interrupt it. Rather, he should alert them by saying "SubhanAllah" (Glory be to Allah) or raising his voice in recitation or similar actions. It is legislated for him to shorten the prayer, then answer the call after completing it. As for a supererogatory (nafl) prayer, if he knows that his parents do not dislike him completing the prayer, he should complete it then answer them. But if he knows they dislike it, he should interrupt it, answer them, and then restart the prayer. This is supported by the hadith of Juraij, and the scholars' saying that the correct action for him was to answer her because he was in a supererogatory prayer and answering the mother is obligatory. He could have shortened his prayer, answered her, then returned to his prayer. As for the obligatory prayer, it is not interrupted except out of necessity.