Why did Mike still kill his brother in Godfather 2?

It is not that there is no forgiveness all the time, but that it cannot be forgiven unconditionally. Give you the steps, you have to go down by yourself.

At least three attempts were made to forgive Fredo, but in the end they were all more disappointed.

Refer to my other answer:

The first part has laid two foreshadowings

The old godfather was assassinated at the fruit stall, and Fredo was unable to hold his gun until the Assassins escaped. After the Assassin escaped, he crouched in place and cried, and did not even call an ambulance, which objectively shows Fredo's cowardice and incompetence. And in the underworld, only blood but incompetent and cowardly people, what will happen to the good end; Fredo was sent to the Nevada casino by Sonny, did not know how the casino worked to get more information for the family, and also fooled around with the casino waiter, the most angry as a Corleone kneeling to lick Moglin, when Mike and Morgelin clashed, he instinctively elbowed out. Even harshly blaming Mike (who should have thought he was an older brother after all, qualified to scold his brother--- for being stupid enough to teach his current godfather a lesson) here Mike has seriously warned him not to have another time (elbow out).

Betraying the family & Mike to Rose, Mike is assassinated.

After arriving in Cuba, Fredo cooperated with Rose and his men in acting, pretending not to know, only to expose himself after drinking a sentence. Mike finally realizes that the adulterer is his brother, and after repeated confirmation, Fredo is still cheating on him, hurting feelings + insulting IQ. However, just after the victory of the Cuban Revolutionary Army and everyone rushed to escape, Mike was willing to forgive him, calling him to get in the car and flee Cuba, even saying "You are still my brother", but Frey chose to run alone, once again giving up the opportunity to be forgiven.

The family is about to be tried and abandoned

After talking to Tom, Mike finds Fredo and hopes he can provide some useful information to help the family. But at this time, Fredo was still stressing that he did not know, or squeezing toothpaste to give some useless information. Face Mike Undead Several Times Confirmed Ask Him Anything More? When the time came, Fredo chose to complain and complain, believing that the family was sorry for himself. Although he seemed sincere and seemed to be trying to explain, he actually chose to stand with the enemy at this time and gave up his last chance. Mike finally utterly despairs of "You're nothing to me now". In the final shot, Fredo is paralyzed in place, and that's it. In the end, he still did not choose to help his family and sentenced himself to death.

Most importantly, he had to die for the sake of his family

After all, Fredo was the second eldest son of the family and knew too much about the family. Pantanguli once misjudged the case, and although the case was overturned in court, he had to commit suicide in prison to apologize. Fredo was tired, even though his surname was Corleone, and he had died many times. Cowardly/stupid, he is completely unable to keep the bottom line in the face of threats/temptations, and under the circumstances of the time, he is almost certain to bring disaster to the family one day in the future. This should be the biggest reason why Mike can't keep him alive in the end, as the godfather, he must solve the family's time bomb.

At his mother's funeral, Fredo asks to see Mike.

Here I believe that perhaps Mike had a little looseness (and probably not), such as driving him back to his old Sicilian home. But the camera is particularly interesting, when Fredo kneels to hug Mike, his hand still seems to be touching mike's waist for a gun; at the end of the day, cowardly he still does not choose to believe. So this last half-chance was gone. Mike's face suddenly cooled, and his eyes looked at the killer.

Nonsense two sentences:

In this movie, Fredo's character is actually a dou who can't be supported, pit daddy pit brother pit family, elbow out, betray the family but still feel that he should get more from the family; although there are some small details to prove that this character is not completely useless (such as the family drama with his niece, etc.), but also from the mafia family in the environment at that time, stupid and cowardly and unprincipled eventually killed him.

In the plot of killing Fredo, Mike experienced many betrayals, with forgiveness; he and his brother alone gave him a chance to wake up, but without success; he also took the initiative to communicate with other family members to adjust his mentality. In fact, this episode is the climax of the second part, "killing one of the families in order to protect the family." The cruel spell sublimates the height of the whole film to some extent.