Whenever Allah's Messenger (ﷺ) became ill, he used to recite the Muawidhatan (i.e. the last two surahs of the Qur'an) and blow his breath over himself (after their recitation ) and rubbed his hands over his body. So when he was afflicted with his
fatal illness. I started reciting the Muawidhatan and blowing my breath over him as he used to do and then I rubbed the hand of the Prophet (ﷺ) over his body.
Sahih al-Bukhari Book 64, Hadith 460