Mishkat al-Masabih 1564
She said :
I saw the Prophet when he was dying. He had a drinking-cup containing water, and he would put his hand into the cup, then wipe his face, then say, “O God, help me to bear the evils of death,” or, “the pangs of death.” 

Tirmidhi and Ibn Majah transmitted it.
وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: رَأَيْتُ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ وَهُوَ بِالْمَوْتِ وَعِنْدَهُ قَدَحٌ فِيهِ مَاءٌ وَهُوَ يُدْخِلُ يَدَهُ فِي الْقَدَحِ ثُمَّ يَمْسَحُ وَجْهَهُ ثُمَّ يَقُولُ: «اللَّهُمَّ أَعِنِّي عَلَى مُنْكَرَاتِ الْمَوْتِ أَوْ سَكَرَاتِ الْمَوْتِ» . رَوَاهُ التِّرْمِذِيُّ وَابْنُ مَاجَهْ