What is the expiation for someone who caused an accident that led to the death of his wife, daughter, and fetus, and does he fast for each one separately?

"Upon your friend and his 'Aqilah (male relatives on the father's side) is the blood money (Diyah) for the wife and the daughter. There is nothing due for the fetus. He does not inherit anything from this Diyah. He must offer expiation (Kaffarah) by freeing a believing slave for each of them (the wife and daughter). If he cannot find one, then he must fast for two consecutive months for each one. However, if he did not commit an error or cause the accident, or violate traffic laws, and did not fall short in avoiding the accident, then there is no expiation or blood money due upon him."