Dua 33 Recite this supplication in the qunoot during prayer for your parents:
(Surah Nuh (71), Verse 28)

رَّبِّ ٱغْفِرْ لِى وَلِوَٰلِدَىَّ وَلِمَن دَخَلَ بَيْتِىَ مُؤْمِنًا وَلِلْمُؤْمِنِينَ وَٱلْمُؤْمِنَـٰتِ وَلَا تَزِدِ ٱلظَّـٰلِمِينَ إِلَّا تَبَارًۢا

Rabbigh fir lee wa liwaa lidaiya wa liman dakhala baitiya mu'minanw wa lil mu'mineena wal mu'minaati wa laa tazidiz zaalimeena illaa tabaaraa.

My Lord! Forgive me and my parents, and whoever enters my house in faith, and the faithful men and women, and do not increase the wrongdoers in anything but ruin.

(Surah Nuh (71), Verse 28)

This is the supplication recite by Prophet Nuh (A.S.) when his people rejected his message. You may recite this supplication in the Qunoot during prayers, especially for your parents.