When is the fasting of two consecutive months for every child who died as a result of a car accident? Is there a specific or preferred time to start the fast? Is it permissible to separate the fasting between the two months for each deceased person? What are the other duties or conditions of validity related to this?

The killer's 'aqila (male relatives on the paternal side) must pay the blood money (diyya) to the family of the deceased, unless they choose to forgo it as charity. The killer is also obliged to offer expiation (kaffara), which is the freeing of a believing slave for each life taken. If unable to do so, then it is fasting for two consecutive months for each life. The continuity of the fast is required for each pair of months individually, but the expiations themselves do not need to be continuous. There is no specific time limit for the expiation; it remains an obligation upon the killer until he completes the fast, though it is better to perform it promptly.