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.
مَا كَانَ لِلنَّبِيِّ وَالَّذِينَ آمَنُوا أَنْ يَسْتَغْفِرُوا لِلْمُشْرِكِينَ وَلَوْ كَانُوا أُولِي قُرْبَىٰ مِنْ بَعْدِ مَا تَبَيَّنَ لَهُمْ أَنَّهُمْ أَصْحَابُ الْجَحِيمِ