My 19yo sister is still like this and unfortunately, I'm pretty sure I was oblivious to the world around me too, until I had to go out on my own and pay my own way.

Oh how I miss the bliss of ignorance and only having to worry about myself Although, you couldn't pay me enough to go back there!

The only tactic I can think of would be to possibly have the 3 of you sit down together and talk about how you all feel, draw up a 'contract' (or just talk about) for respecting house rules and the possible consequences of not following the rules, while at the same time praising her for all the good things she does do already.