It was narrated from 'Abdul-Hamid bin Salamah, from his father, from his grandfather, that : his parents referred their dispute to the Prophet (ﷺ), and one of them was a disbeliever. He (the Prophet (ﷺ)) said: “O Allah, guide him,” and he turned towards the Muslim, and he ruled that he should go with that parent.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا إِسْمَاعِيلُ ابْنُ عُلَيَّةَ، عَنْ عُثْمَانَ الْبَتِّيِّ، عَنْ عَبْدِ الْحَمِيدِ بْنِ سَلَمَةَ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، أَنَّ أَبَوَيْهِ، اخْتَصَمَا إِلَى النَّبِيِّ صلى الله عليه وسلم أَحَدُهُمَا كَافِرٌ وَالآخَرُ مُسْلِمٌ فَخَيَّرَهُ فَتَوَجَّهَ إِلَى الْكَافِرِ فَقَالَ " اللَّهُمَّ اهْدِهِ " . فَتَوَجَّهَ إِلَى الْمُسْلِمِ فَقَضَى لَهُ بِهِ .
sunnah.com