After the Ako-jo Castle's surrender, Nobukiyo lived in Nara City and Kyoto City with Nobutoyo, his older brother, but then disowned Nobutoyo because the brother withdrew from the alliance as he had failed to show enough allegiance when Oishi returned his written oath to judge his loyalty.
赤穂城開城後は兄信豊とともに奈良市や京都市で暮らしていたが、元禄15年(1702年)8月の大石の神文返しを機に兄が脱盟したため、兄とは義絶。