As noted earlier, rather than involve yourself further in the situation, recommend that he approach the elders.
لكِنَّهُمْ فِي ٱلْوَاقِعِ لَنْ يُطْرَدُوا مِنَ ٱلْجَمَاعَةِ إِذَا تَوَقَّفُوا عَنِ ٱلْمُمَارَسَةِ ٱلْخَاطِئَةِ وَتَابُوا تَوْبَةً أَصِيلَةً .‏