Question: 
Is it permissible for the one who says directly after the Salaam ( of concluding the prayer), he seeks from those praying to mention Al Faatiha for cure? 
Imam Muqbil Ibn Haadee Al Waadiee:
No, this Is an innovation, As Sanaanee said in Subulis Salaam after he mentioned the supplications which have been reported after the prayer, such as 
اللهم اعني على ذكرك و شكرك و حسن عبادتك, 
And such as the reading of Ayatul Kursi, At Tasbeeh (saying Subhanallah) At Takbeer (saying Allahu Akbar) At Tahleel (saying La ilaaha Illallah).
He says: And as for the statement: Al Faatiha due to such and such intention, then it is an innovation, it hasn’t been affirmed from the prophet Sallallahu alaihi wassallam.
و الله المستعان.
End. 
Translator’s Note :Imam As Sanaani statement can be found in Subulus Salaam in the explanation of the Hadeeth of Abu Huraira number 313 
Volume 1 page 303 print Ihya At Turaath. 
Translated by Majid al-Afghaani.