Purity: Ghusl for a Person Who Died in a State of Janabah or Hayd
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 554:
If someone dies while in the state of ḥayḍ or janabah, it is not necessary to give that person the ghusl for ḥayḍ or the ghusl for janabah; rather, the ghusl given to a corpse is sufficient.
-Ayatullah Sistani, Practical Laws of Islam, Purification (Taharah)