know little and care less

know little and care less (about someone or something)

To have only a passing knowledge and absolutely no concern about someone or something. A: "Don't you have any family who would take you in?" A: "I had a half-brother who lived upstate, but the last time I checked, he knew little and cared less about what happens to me." There's no point getting frustrated at the computer. It's just a machine—it knows little and cares less about what you want it to do, only what you tell it to do.
See also: and, care, know, less, little, someone

know little (or nothing) and care less

be completely unconcerned about something; be studiously ignorant.
See also: and, care, know, less, little