Without taking sides, he can reason with the couple on Bible principles, perhaps using those found in chapter 3 of the book The Secret of Family Happiness.
لِنَفْتَرِضْ أَنَّ زَوْجَيْنِ مَسِيحِيَّيْنِ طَلَبَا مُسَاعَدَةَ أَحَدِ ٱلشُّيُوخِ لِأَنَّهُمَا يَتَشَاجَرَانِ كَثِيرًا .‏