Causing the death of his brother and cousin

Q: When our fourteen year old son wanted to go to (Part No. 21; Page No. 336) offer Friday Prayer, his younger brother aged one year and ten months wanted to go with him. Their sister prevented him but he kept crying. Upon hearing his cries, the mother told his sister to let him go. He went out from another door and headed towards the back of the car. When his brother was reversing the car, not knowing that his brother was behind it, he ran over him and he died instantly. Patiently, we endured the calamity seeking Allah's reward. Now, should the mother and the brother offer a Kaffarah (expiation) or not? May Allah reward you with the best!

A: Your son does not have to offer a Kaffarah, if he has not reached the age of fifteen unless he is grown enough to discharge seminal fluid with desire whether through a wet dream or so, or has pubic hair. If so, he has to offer expiation i.e. Freeing a Muslim slave. If he is unable to do so, he has to fast for two successive months.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.