Does a swimming lifeguard guarantee the Diyah (blood money) and is he obligated to perform the Kaffarah (expiation) in cases of death that occur in the place under his supervision?

The person working as a lifeguard is a private employee (ajeer khass). A private employee is not liable for what is damaged under their care unless there is negligence (tafreett) or transgression (ta’addi). If the lifeguard does not transgress or act negligently, then there is no blood money (diyah) or expiation (kaffarah) due from them. However, if they transgress or act negligently, then blood money is due from their 'aqilah (male relatives on the father's side) and expiation is due from them. Examples of transgression or negligence include: allowing those who are not proficient in swimming to swim in a dangerous area, or neglecting to monitor swimmers, leading to one of them drowning. This is similar to the wet nurse (dha'ir) or the shepherd not being liable if what is under their care perishes without negligence on their part.