Can a person recite Surah Yaseen 41 times or recite the dua of Prophet Yunus in the whale’s belly 124,000 times for the sick (as is done in a congregation)?
Reciting Sura Yaseen along with the Dua of Prophet Yunus (AS) in this manner has not been recorded as being a practice of the Prophet (SAW), the Sahabahs, the Tabieen and Tabe Tabieen. There is no doubt that there are virtues in the recitation of Sura Yaseen and also supplicating with the Dua of Yunus (AS). However, there is no evidence of this manner which you have described.
And Allah knows best.
Mufti Waseem Khan