Fredo had it coming for this reason

Not because he betrayed Michael. Whether he did it intentionally or not, I don't think that's what got him killed. I believe it was the lack of remorse he showed Michael in the boat house. And worse yet, the jealousy he showed. I think Michael truly wanted to forgive Fredo. He just wanted to find out why Fredo did and what all happened. Remember each time Michael tries to reach out to him? "Fredo, come with me, you're still my brother." Then to Tom: "Where's my brother? Get in touch with him, tell him everything is all right. I know he's scared." And then Michael actually goes to the extent of wanting to hear Fredo'a explanation. And what does Fredo do? He makes it all about himself. "There was something in it for me, on my own... I was stepped over..." Man, seriously? That's what did it. All Fredo had to do was express remorse and guilt and open up to Michael in a deep, sincere apology. And then maybe his life would have been secure. I'm not even sure I blame Michael for what he did... Okay, maybe I do. A little. Fredo was dumb and maybe not capable of understanding the fact that he should have proved he was terribly sorry. But then again, maybe he wasn't sorry. Maybe Fredo DID want Michael dead because he got stepped over so much. But still, Fredo could have had a longer life if he hadn't been so damn selfish and jealous. For years I've watched this film feeling sorry for Fredo, but I've been taking a different path lately. Michael really wanted to help his brother feel safe and protected. But Fredo ruined that.