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Two examples spring to mind, neither exactly your situation: Christopher Tolkien did work on his father's oeuvre, but that's more curation than editing. He did cobble together The Children of Húri...
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#4: Attribution notice removed
Source: https://writers.stackexchange.com/a/28747 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#3: Attribution notice added
Source: https://writers.stackexchange.com/a/28747 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/
#2: Initial revision
Two examples spring to mind, neither exactly your situation: Christopher Tolkien did work on his father's oeuvre, but that's more curation than editing. He did cobble together _The Children of Húrin_ from pieces, but that isn't quite your situation. A more recent but negative exampe is _Go Set a Watchman._ Harper Lee is reportedly no longer mentally competent, and [various parties, including a lawyer and an agent,](https://en.wikipedia.org/wiki/Go_Set_a_Watchman) found and developed an early manuscript of Lee's until it was a fully-standing novel. While the publisher originally tried to present it as a prequel to _To Kill a Mockingbird,_ critics soon determined it was a rough draft of that novel rather than a separate story set before it. _Watchman_ presents Atticus Finch as racist rather than the equality-supporting man he is in _Mockingbird,_ which deeply upset many readers. (In your particular case, since you edited this writer's work when he was alive, I think you should have more say, but that's neither here nor there.)