Du'a for protection from the punishment of the grave

اللَّهُمَّ أَعِذْهُ مِنْ عَذَابِ الْقَبْرِ

Allahumma a'idh-hu min 'adhabil-qabr

O Allah protect him from the punishment of the grave.

Adapted from Ṣaḥīḥ Muslim 963, which reads "اللَّهُمَّ اغْفِرْ لَهُ وَارْحَمْهُ... وَأَعِذْهُ مِنْ عَذَابِ الْقَبْرِ"