Dr. Pestell sold a large portion of his shares in October and November 2019 ranging from $.28-$.33 before the Vyera agreement. Here is the filing that shows these sales and notes that he is no longer owns 5% of the outstanding shares (no longer required to report sales). Pretty sure myself and others were buying these bargain dips around this time (although those were the darkest days for CYDY since I've been invested). https://www.sec.gov/Archives/edgar/data/1175680/000110465919069744/a19-24455_1sc13da.htm
My guess is these were sold based on legal advice from his counsel or the perception of being a large shareholder during the legal procedures and has nothing to do with the science as he is still publishing papers on leronlimab (as others noted).