Was Pi's Act Morally Justified?

Pi is stranded in the middle of the pacific with his mother, the cook (an ill tempered, greedy French man), and a Chinese sailor. The sailor broke his leg while jumping into the lifeboat. The cook cuts the leg off and tries to use it as bait to catch fish. The sailor dies and the cook butchers and eats him. Pi and his mother try to stop him. He kills Pi’s mother and throws her head towards Pi. Later Pi fights the cook and kills him in a moment of revenge and self preservation

Was Pi’s act morally justified? As moral arguments are best proven by analogies, let us consider four people in the same situation but a different setting. Four strangers (namely A,B,C,D) are stuck in a lifeboat. A has a gun and decides to kill B (who was already injured
But then again we must ask ourselves, if there is any significant difference between the hypothetical and Pi’s scenario. Well of course there is a difference, the cook kills Pi’s mother whereas in the hypothetical all four of them are strangers to each other. So now emotional angles come into play. Lets assume C is D’s mother. This would hardly affect D’s decision to kill A but it might just strengthen his resolve to carry out A’s execution because now D has three motives to kill A, self defence, hunger and the new addition, revenge. Revenge can justify any act emotionally if not
However keen and the people in favour of his verdict treat law more like a game in which the rules are strictly defined and the breaking of those rules dictates a fixed penalty. No law is absolute because no lawmaker is infallible and this one surely is because not only the law is incomplete and in-comprehensive but also there is no scope for the interpretation of law. If we were to follow law by the word then even if someone killed a dog he would be hanged as he has “wilfully taken the life of another” for that matter if a cop shot a terrorist, instead of getting a medal he would get a death penalty. Martin Luther King Jr. correctly said “Law and order exist for the purpose of establishing justice and when they fail in this purpose they become dangerously structured dams that block the flow of social progress”. The law needs to be more elaborate and cover certain aspects like self-defence, when is it applicable, whom is applicable on and provisions for special cases. If the law is revised and Pi’s case is re-evaluated under the new law, I am sure he will live to see another