What is the ruling on retribution (Qisas) when one of several brothers kills another, followed by further killings among the remaining brothers?

Primary text

If the eldest of four brothers kills the second, and then the third kills the youngest, retribution (Qisas) against the eldest is waived. This is because upon the death of the second, his inheritance became equally split between the third and the youngest. When the third killed the youngest, he did not inherit from him, but the eldest inherited from the youngest. Thus, the eldest inherited half of his own blood money (blood due to himself) and the entire inheritance of the youngest. Because he inherited a portion of his own blood money, Qisas against him is waived. He is entitled to Qisas against the youngest brother, and he inherits from him according to the apparent position of the Madhhab. If Qisas is executed against the youngest, the eldest inherits from him, as do his other three brothers.