Du'a Before Sleeping: Entrusting Oneself
الفئة: Sleep
اللَّهُمَّ أَسْلَمْتُ نَفْسِي إِلَيْكَ وَفَوَّضْتُ أَمْرِي إِلَيْكَ وَأَلْجَأْتُ ظَهْرِي إِلَيْكَ رَغْبَةً وَرَهْبَةً إِلَيْكَ لَا مَلْجَأَ وَلَا مَنْجَا مِنْكَ إِلَّا إِلَيْكَ آمَنْتُ بِكِتَابِكَ الَّذِي أَنْزَلْتَ وَنَبِيِّكَ الَّذِي أَرْسَلْتَ
Allaahumma aslamtu nafsee ilayka, wa fawwadtu amree ilayka, wa alja'tu zahree ilayka, raghbatan wa rahbatan ilayka, laa malja'a wa laa manjaa minka illaa ilayka, aamantu bikitaabikal-lazee anzalta wa nabiyyikal-lazee arsalt.
O Allah, I submit myself to You, and I entrust my affair to You, and I turn my back to You (for refuge) out of hope and fear of You. There is no refuge and no escape from You except to You. I believe in Your Book which You have revealed, and Your Prophet whom You have sent., Muhsin Khan (en)
Sahih al-Bukhari 6313
Make this the last thing you say before sleep.
If he dies that night, he dies upon the fitrah (natural disposition / Islam).