One of the finest acts of kindness is for a man to treat his father’s friends in a kindly way after he has departed. (Using translation from Abū Dāʾūd 5143)
أَنَّهُ قَالَ قَالَ رَسُولُ اللهِ ﷺ إِنَّ أَبَرَّ الْبِرِّ صِلَةُ الْمَرْءِ أَهْلَ وُدِّ أَبِيهِ بَعْدَ أَنْ يُوَلِّيَ