He who offered prayer for the dead, for him is the reward of one qirat, and he who attended its burial, he would have two qirats as his reward. And qirat is equivalent to Uhud.
عَنْ ثَوْبَانَ مَوْلَى رَسُولِ اللَّهِ ﷺ أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ مَنْ صَلَّى عَلَى جَنَازَةٍ فَلَهُ قِيرَاطٌ فَإِنْ شَهِدَ دَفْنَهَا فَلَهُ قِيرَاطَانِ الْقِيرَاطُ مِثْلُ أُحُدٍ