O Allah, forgive [name of the person] and elevate his station among those who are guided. Send him along the path of those who came before, and forgive us and him, O Lord of the worlds. Enlarge for him his grave and shed light upon him in it.
اللهُـمِّ اغْفِـرْ لِـ-فلان باسـمه- وَارْفَعْ دَرَجَتَـهُ في المَهْـدِييـن ، وَاخْـلُفْـهُ في عَقِـبِهِ في الغابِـرين، وَاغْفِـرْ لَنـا وَلَـهُ يا رَبَّ العـالَمـين، وَافْسَـحْ لَهُ في قَبْـرِهِ وَنَـوِّرْ لَهُ فيه
Allaahummaghfir li (name of the person) warfa’ darajatahu fil-mahdiyyeena, wakhlufhu fee ‘aqibihi fil-ghaabireena, waghfir-lanaa wa lahu yaa Rabbal-‘aalameena, wafsah lahu fee qabrihi wa nawwir lahu feeh
Muslim 2/634.