What is the ruling on an employee guaranteeing their debt with their job salary, which may be interrupted or changed, and what are the implications of that if the employee dies? Is the debt paid from the salary allocated to the heirs or from the entire estate, and do the heirs have the right to reclaim what was deducted from the deceased's salary for the bank's account?

If the intention behind guaranteeing a debt with a salary is to pledge the salary as security for the debt, then this involves significant gharar (definition) (excessive uncertainty) which affects the validity of the security. This is because the salary is not yet in existence and its future existence is uncertain, being contingent on both presence and absence. Anything of this nature cannot validly be used to secure a debt.