Purity: Repetition of Salat al‑Mayyit
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 595:
The opinion of some jurists is that it is disapproved to perform salat al‑mayyit a number of times. However, this matter is not established, and if the deceased is a learned and God-wary person, there is no problem in considering it not disapproved.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)