What are the Sharia rulings applicable to a driver who was involved in a car rollover accident that led to the death of his mother-in-law, knowing that he was feeling exhausted, drove the car after a short period of sleep, tried to stay awake with an energy drink, and was unable to stop for rest because he postponed it to please his companions in the car, which resulted in him losing control of the vehicle?

If the driver takes all safety precautions and does not act negligently, then the consequences of an accident are considered wasted and he is not liable. However, if he is negligent or careless, then he is responsible for the damages resulting from the accident. According to Sheikh Al-Uthaymeen, if the accident was due to negligence or transgression on the part of the driver, then he is liable for diyah (blood money) and kaffarah (expiation). If not, then he is not liable for anything. It is highly probable that there was negligence in this case, as you entered traffic while exhausted and fighting sleep, which makes the killing an act of error. Therefore, diyah and kaffarah are incumbent upon you, as well as responsibility for all other resulting damages.