When someone fell ill, the Prophet would recite one of these four du'as for them.
#1: It is recommended to touch the area of pain with the right hand while reciting this supplication:
Allahuma rabbi-nas adhhabal ba'sa, ashfi wa entashafi, la shifa' illa shifa'uka shifa' la yughadiru saqama.
Oh Allah! The Sustainer of Mankind! Remove the illness, cure the disease. You are the One Who cures. There is no cure except Your cure. Grant us a cure that leaves no illness.
#2 Repeat the following du'a seven times:
'As'alu Allah al 'azim rabbil 'arshil azim an yashifika.
I ask Allah, the Mighty, the Lord of the Mighty Throne, to cure you.
#3: Another du'a from the Sunnah:
Rabbana 'atinaa fid dunyaa hasanat wafil aakhirati hasana taw wa qinaa azaaban naar.
Oh Allah! Our Lord and Sustainer! Grant us good in this world and good in the Hereafter, and save us from the
Fire of Jahannam (Hell).
#4: This du'a should be recited while the sick person places his or her right hand on the area of pain. The word "bismillah" should be repeated three times, and the entire supplication should be recited seven times:
A'oozu bi'izzatillaahi wa qudratihi min sharri maa ajidu wa uhaaziru.
I seek protection in the might of Allah and His power from the evil of what I am experiencing and of what I fear.
I will pray for the full recovery of your brother my friend...