Hisao has now become something of an expert in home care, but says he couldn't possibly cope without the additional help from his siblings.

CNN: Alone in the Big City

Hisao is prematurely graying but apparently content with what he does.

CNN: Alone in the Big City

Most of the responsibility falls to elder son Hisao, 50, who lives next door and works shortened hours in his brother's advertising firm so that he can devote more time to their mother.

CNN: Alone in the Big City