Prayer: Death of the Hired Person Before Completion
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1526
If a person is hired to, for example, perform the prayers of a deceased person within the period of one year, and if he dies before the end of one year, then another person must be hired to perform the prayers that are known not to have been performed [by the previous hired person]. If it is deemed probable that the hired person did not perform them, another person must still be hired based on obligatory precaution.