Just for your information, in "The Nakamura Family Genealogy" (the title inside the book: the origins of the Nakamura clan in Inshu [Inaba Province]) it is recorded that Harutsugu and his younger brother Harukuni (春国) succeeded to the Nakamura clan.
参考までにだが『中村家譜』（内題・因州中村家由来）には中村家を継承したのは春続の弟・春国と記されている。