مَا كَانَ لِلنَّبِيِّ وَالَّذِيْنَ اٰمَنُوْٓا اَنْ يَّسْتَغْفِرُوْا لِلْمُشْرِكِيْنَ وَلَوْ كَانُوْٓا اُولِيْ قُرْبٰى مِنْۢ بَعْدِ مَا تَبَيَّنَ لَهُمْ اَنَّهُمْ اَصْحٰبُ الْجَحِيْمِ ( التوبة: ١١٣ )
Maa kaana lin nabiyyi wallazeena aamanooo ai yastaghfiroo lilmushrikeena wa law kaanoo ulee qurbaa mim ba'di maa tabiyana lahum annahum Ashaabul jaheem (at-Tawbah 9:113)
It is not for the Prophet and those who have believed to ask forgiveness for the polytheists, even if they were relatives, after it has become clear to them that they are companions of Hellfire. (At-Tawbah  : 113)
1 Mufti Taqi Usmani
It is not (permissible) for the Prophet and the believers to seek forgiveness for the Mushriks, even if they are kinsmen, after it became clear to them that they are the people of hell.