Is the accident that resulted in the death of the sister and the injury of the daughter considered manslaughter that necessitates blood money or fasting, given that the cause of the accident was a tire blowout, and the driver does not remember his speed but thought it was above the limit, and he did not remind his sister to fasten her seatbelt?

If a driver causes an accident resulting in fatalities due to his negligence in safety procedures (such as excessive speed or using an unfit vehicle), this is considered unintentional killing, which necessitates Diyya (blood money) and Kaffara (expiation) for each life lost. The Kaffara is freeing a believing slave, or, for whoever cannot find one, fasting for two consecutive months. The Diyya is paid by the killer's family to the heirs of the deceased.

As for injuries, if a daughter's injury reaches one-third of the Diyya or more, it is borne by the perpetrator's family. If it is less than one-third, it is borne by the perpetrator himself from his own wealth. Therefore, the driver's family is obligated to pay the Diyya for his sister, and for his daughter's injury if it reaches one-third of the Diyya (otherwise it is on the driver himself). He is also obligated to perform the Kaffara, unless the heirs forgive him.