What happened to Dr. Osamu Terada?

Dr. Osamu Terada, circa 1931. Taken in NYC. Research Pathologist. Family name was Hata. Father was from Nara, Japan. Biological mother was from France. Osamu was born Sept 1886. Stepmother in Nara, later in Sakai City. Immigrated to US circa 1905. Traveled back to Japan in 1922, then returned to US.

Dr. Terada was last seen in early 1940s in NYC during WWII, while working as a 'Korean houseboy'. Family has no idea what happened to him. Any information appreciated.