This is a rather morbid question; sorry for that.
A friend recently passed away. Prior to passing, he had submitted some of his work to a journal. Journal editor has reached out to see if I could help with some non-controversial copy editing and providing a source file (only PDF had been submitted). We're going to confirm with the family that they're OK with this. If we proceed, is there anything I can do short of entirely recreating the tex file by hand?