Is expiation incumbent upon the mother, in addition to the expiation for involuntary manslaughter upon the paternal uncle, if her child dies as a result of being run over by his paternal uncle's car in front of the house, on the grounds of her negligence?

In this case, expiation is incumbent upon the uncle because he directly caused the accidental killing, and the blood money (diyya) is to be paid by his 'aqila (male relatives on his father's side). There is no liability upon the mother, as the child's death occurred through someone else's direct action. The jurisprudential rule states that when a direct actor and an indirect cause combine, the ruling is attributed to the direct actor. Furthermore, there is no sin upon the mother, given that the child was three years old and in front of his grandparents' house, if this was a normal occurrence for them in that environment.