Sonny, some people here anchor their belief that Sonny died in '49 to the presence of a "Dewey for President" poster on a wall when Sonny beats up Carlo. But, Thomas E. Dewey, the Republican Presidential candidate in '48, also was their candidate in '44, so the poster could be part of support for an earlier date for Sonny's death.
The screenplay has Sonny's murder occuring in the Spring of '46. But in Jenny M. Jones' book you get a glimpse of FFC's Sicilian notes that state those scenes take place in 1948.
The whole timeline is so screwed up. If the '48 clues above punctuate the timeline, then we must suppose that after murdering Sollozzo, Michael was in exile in Sicily for most of '46, all of '47, and some undetermined part of '48 (The Republican convention was held in June). So, sonny is still alive at that time as he beats up Carlo. Thus, prior to Sonny's death in '48, Vito lay in his sick bed for all of '46, all of '47, and some undetermined part of '48; possibly 2.5 years. Seems implausible.
