Yeah his claim is quite absurd really. If it was a weaker stockfish (bad hardware, older version etc.) then maybe. Modern stockfish pretty much crushes any and everyone. A draw alone would be extremely impressive, and maybe doable with enough luck from a top player. But even that is very far fetched nowadays. Let alone actually winning.
Elsewhere in the thread he revealed that he achieved these results around the year 2015, which means we was playing against Stockfish 6 or earlier, estimated to have about 400 less ELO than today's Stockfish 18. Stockfish 6 didn't even have NNUE, so the real issue seems to be that he thinks his results from 2015 hold any relevance to the chess engines of today.