أحسن الله إليكم My aunts husband has cancer and phone called to tell my mom to read surah al fatihah many times because they want to do khatma, by dividing like this to different people. And at the end make a du'a. If this is a bid'ah, how do i tell my mom its bad to do this as she wont understand?

Ustadh AbdulAziz al-Haqqan

Do the ruqyah of the Prophet ﷺ which is the best ruqyah, and remember we should never make up stuff in the religion. I advise u to do what is in hisn al Muslim