involuntary manslaughter should bear a Kaffarah (expiation) over and above the Diyah (blood money), which is freeing a believing slave. If he could not do that, he should fast for two consecutive months. You can fast for two months consecutively this year, then two successive months after a while, and (Part No. 21; Page No. 288) two other successive months later on. According to the soundest opinion of the scholars, Kaffarah by serving food does not suffice. This is based on the Saying of Allah (Exalted be He):
It is not for a believer to kill a believer except (that it be) by mistake; and whosoever kills a believer by mistake, (it is ordained that) he must set free a believing slave and a compensation (blood-money, i.e. Diya) be given to the deceased’s family unless they remit it. If the deceased belonged to a people at war with you and he was a believer, the freeing of a believing slave (is prescribed); and if he belonged to a people with whom you have a treaty of mutual alliance, compensation (blood-money - Diya) must be paid to his family, and a believing slave must be freed. And whoso finds this (the penance of freeing a slave) beyond his means, he must fast for two consecutive months in order to seek repentance from Allâh. And Allâh is Ever All-Knowing, All-Wise.
In this honorable Qur'anic Ayah (verse), which gives a detailed explanation, Allah (Exalted be He) makes no mention of serving food. This is proof that what is ordained is the freeing of a slave, and for those who find this (the penance of freeing a slave) beyond his means, then Sawm is obligatory. There is no other Kaffarah.May Allah grant us success. May peace and blessings be upon our Prophet, his family and Companions.