Dua when hearing of the demise of an Acquaintance

إِنَّا لِلَّهِ وَإِنَّا إِلَيْهِ رَاجِعُونَ، وَإِنَّا إِلَى رَبِّنَا لَمُنْقَلِبُونَ، اللهُمَّ
اكْتُبْهُ فِي الْمُحْسِنِينَ، وَاجْعَلْ كِتَابَهُ فِي عِلِّيِّينَ، وَاخْلُفْ
عَقِبَهُ فِي الْآخِرِينَ، اللهُمَّ لَا تَحْرِمْنَا أَجْرَهُ، وَلَا تَفْتِنَّا بَعْدَهُ

Verily we belong to Allâh and we will return to Him. We will go back
to Our Sustainer. O Allâh, record hom amongst the pious, plce his
book of deeds in Illiyîn, and look after those he has left behind. O`
Allâh, do not deprive us of his reward, and do not place us into trials
after him. 
(Tabrani in Kabir, Duâ of Tabrani, Ibnus Sunni)