What is the expiation and punishment for someone who leaves another person to drown in order to save himself, and can he atone for his sin despite being unable to reach the family of the drowned person?

Transporting the boy and helping him cross the river is considered an act of negligence that necessitates a guarantee (daman), because Shafi'i jurists have stipulated that if someone takes a child into water to cross, and the child drowns, then that person is liable. This liability entails two matters: blood money (diyah) to be paid by the 'Aqilah (male agnates), and expiation (kaffarah), which is fasting for two consecutive months. If there is no 'Aqilah or they refuse to pay, then the diyah is waived according to some jurists, but the kaffarah of fasting for two consecutive months remains obligatory.