Do the brothers have the right to demand the financial indemnity available after the death of their brother in an accident, in the presence of the father and mother, or is this considered an inheritance?

The blood money for a life is inherited like all other assets of the deceased. Each heir receives their appointed share from it, with the exception of the killer, based on the Prophet's (peace be upon him) saying: "The killer does not inherit," and Allah's (the Most High) saying: "and blood money surrendered to his family," and the Prophet's (peace be upon him) saying: "The blood money is an inheritance among the heirs of the slain according to their prescribed shares." Blood money is inherited in cases of intentional killing and accidental killing. Consequently, the questioner and his siblings are not entitled to any share of the blood money because they are excluded by their father. Thus, the blood money is distributed as one-sixth to the mother, and the remainder to the father by way of ta'sib (residuary inheritance).