Is the blood money obligatory on the father even if a judicial ruling has been issued for his imprisonment and payment, if he had not been brought to justice, and is he required to fast for two consecutive months, or is there an alternative to it?

Accidental killing necessitates two things: a mitigated blood money (diyya) to be paid by the 'āqila (male relatives on the father's side), and expiation (kaffāra) which is the freeing of a believing slave. If one cannot find a slave, then it is fasting for two consecutive months. The proof for this is the verse: "It is not for a believer to kill a believer except by mistake. And whoever kills a believer by mistake - then the freeing of a believing slave and a compensation presented to his family [is required] unless they give [it up as] charity. But if he was from a people hostile to you and he was a believer, then the freeing of a believing slave [is alone sufficient]; and if he was from a people with whom you have a treaty of peace and he was a believer, then a compensation presented to his family and the freeing of a believing slave. And whoever does not find [one or afford it] - then a succession of two months of fasting as repentance to Allah. And Allah is ever Knowing and Wise." This ruling does not change with trial or imprisonment.

If the killer is unable to perform the expiation, the majority of scholars hold that nothing else is obligatory upon him. However, some scholars stated the obligation of feeding the poor. If the rightful claimants waive the blood money after the death of their inheritor, they cannot demand it thereafter, based on the rule: "That which is waived does not return." This is unless some of those who waived it are not legally competent to dispose of their rights due to being minors or having unsound judgment, in which case their share of the blood money does not lapse.