That's correct! The text is presented on the source web page as a story, and it does not claim to be factual.
Alexander Grothendieck was indeed awarded the Crafoord Prize, which he rejected. (It was never worth 40 mil francs as the translation above claims. The original French put it at "40 briques" = 400,000, currency not specified, which is much closer to the more accurate 800K SEK ~ 800K FFr that he would have received. The fact that the full amount, 1,6M SEK, would be split between him and Pierre Deligne, whom Grothendieck had denounced, might have contributed to his decision.) Grothendieck's rejection letter was remarkably lucid and articulate: https://www.fermentmagazine.org/quest88.
