The film never reveals what specific assistance Fredo provides Ola and Roth against Michael, how much he knew of their intentions, or what he was offered in return. While in Havana negotiating with Roth, Michael discovers that Fredo is the family traitor behind the assassination attempt on him.
Fredo's decision is most likely a result of resentment toward Michael, by whom he felt he had been passed over. Michael was Fredo's "kid brother," and the fact that their father chose for Michael to take over the "family business" came as a great insult to Fredo, who was neither as intelligent nor as strong.
In film. 1974 The Godfather Part II produced, directed, and co-written (with Mario Puzo) by Francis Ford Coppola, Michael Corleone gives his brother Fredo Corleone the kiss of death after he discovers Fredo's betrayal.
Fredo betrayed his brother to rival gangster Hyman Roth, who used him as a pawn in a plot to destroy the Corleone Family. Fredo provided unspecified information on the Corleone family in return for receiving compensation (what kind is never specified) independently of the family.
What Exactly did Fredo Do to Betray Michael Corleone? | The Godfather 2 Explained
Why did Hyman Roth want Michael dead?
Roth secretly plans to assassinate Michael, partly to avenge Moe Greene's murder (as depicted in The Godfather). Roth instructs Ola to befriend Michael's brother Fredo, who provides Ola (and Roth) information about Michael that enables them to make an attempt on his life.
Roth arrives at the airport and prepares to be taken into Federal Custody in the U.S. Minutes after getting off the plane, he is shot point-blank by Corleone caporegime Rocco Lampone, who was posing as a reporter. Rocco was then shot and killed by federal officers as he was running away.
He would do this because he wouldn't want it to look like he was at all involved in Fredo's death. Fredo drowned while fishing and his body was never recovered. He fell out of the boat and sank and no one could retrieve him on that nice private lake.
Enraged, Sonny speeds towards Connie's apartment in Hell's Kitchen ahead of his bodyguards. At the Long Beach Causeway toll plaza, Barzini's men trap Sonny and shoot him to death. During a meeting with the other crime family dons to establish peace, Vito realizes that Barzini masterminded Sonny's murder.
In the novel, Greene is murdered shortly afterward by Al Neri. At the end of the film, Michael has Greene killed as part of his slaughter of the Corleone family's enemies. Neri surprises Greene while he is getting a massage and shoots him through the eye.
Fredo would have been exiled to a position of no control whatsoever and “managed” for the rest of his natural life. Sonny and Vito would have kept him alive, in a role where he could not hurt them. They would let him live out his days fishing in the compound. Michael was much more ruthless than both Sonny and Vito.
Soon after, while Fredo and Neri are fishing on Lake Tahoe, Neri executes Fredo, while Michael watches from his house. Fredo makes a final appearance in the movie's penultimate scene, a flashback to Vito's birthday party in December 1941.
The biggest clue — as events play out in the screenplay of “Godfaher II” — is when Michael realizes that Fredo is the betrayer in the Corleone organization, as revealed by Fredo's lies. Moreover, it's that Fredo's lies reveal that FREDO WAS WORKING WITH ROTH'S HENCHMAN, Johnny Ola. That is the key.
Ultimately, Tessio betrays Michael by helping arrange his assassination at a peace summit with Barzini and Philip Tattaglia. The summit will be held in Tessio's fiefdom in Brooklyn, where Michael will presumably be safe. In return, Tessio was to inherit the Corleone family upon Michael's death.
Most noteworthy, the novel depicts Clemenza's fatal heart attack (mentioned in The Godfather Part II), and the many conspiracy theories that he had actually been murdered by the Rosato Brothers, former Corleone soldiers who had formed their own gang after a dispute over the future of the family.
Fredo was aware that Hyman was angry with Michael's aggressiveness in Las Vegas, and he simply allowed Hyman to attempt to kill Michael so that he could hopefully claim the title of Don Corleone.
The third and final film in the Godfather saga, The Godfather: Part III, set in 1979, explains that Hagen had died a few years earlier. His son, Andrew, is ordained to the priesthood, and is assigned to the Vatican on Michael's recommendation. While talking with Andrew, Michael remembers Hagen fondly as a great lawyer.
Michael publicly appears to forgive Fredo, but later has him killed after Connie organizes a visit for Kay behind Michael's back which breaks the agreement. Connie later says that Fredo had drowned, feigning ignorance of the truth. After Michael and Kay's divorce, Connie helps care for Michael's children.
In the late summer of 1948, Sonny Corleone was lured into a trap and was killed at the Jones Beach Causeway by Barzini family hitmen in order to avenge Carlo. The hit was engineered by Emilio Barzini after Carlo, angered at the loss of his income and at the fact that Sonny had beaten him, helped set it up.
A rift grows between Pentangeli and Michael, however, that eventually results in Pentangeli betraying the family. Pentangeli's character was created in The Godfather Part II by Coppola and Puzo due to actor Richard Castellano not reprising his role as Clemenza in the sequel.
Clemenza was scheduled to return in The Godfather Part II, but due to a disagreement between Castellano and Paramount, his character was killed off and was replaced by Frank Pentangeli.
