Carlo never made this bones

I think in the book and movie they should of had Carlo kill Some other Don, like the one he had was payed to help kill Sonny. I think he might have lived then

In both the book and the movie, when Hagen asks Don Vito if they should give his new son in law a good position in the family, Vito replies "Never! Give him a living but never anything important!" Carlo eventually began to see that he would never amount to anything important within the Corleone family, so he became bitter and his bitterness and resentment eventually led to his setting up Santino! Michael eventually gives Carlo a false hope and comfort within the family, telling him that he would now be his right hand man in Nevada! It was all done to relax Carlo and erase any thoughts in his mind that the Corleones suspected him of setting up Sonny. No, Carlo could NEVER be trusted within the Corleone empire!

Don Cardi

Murdering another family Don would have been too large of a task for Carlo Rizzi. He is obviously not very bright.

No matter what Carlo would have done, he still would have been killed. He is the reason that Sonny died, Michael will never forget or forgive that.