Many people write books on interesting subjects posthumously (biographies come to mind). I believe it would be up to the descendants of Feynman to sue if due legal etiquettes were not maintained. Having said that, all famous Feynman books like the Feynman lectures, Surely You're Joking Mr. Feynman, Please of finding things out, etc are edited pieces of Feynman's recorded audio, no doubt about that.

Honestly, my problem with the video in question is that its tone unjustly attempts to denigrate Feynman (starting with the clickbaity title itself, a sham legacy? really?) by trying to frame the narrative that his supposed works were not his to begin with. The comments in that video validate this sentiment to the point that people joke about him not existing at all? If this is the central takeaway of the video then I'm honestly glad that I didn't waste precisious few hours of my life on such misleading content. Feel free to correct me though.

To me, Feynman is iconic because of the way he communicates. Of course, there is a disjunction between the man and his ideas and I'm not unwilling to believe that he had some flaws.