Then cut her off by that I mean stop giving her money. This is gonna sound horrible but even if you raised her (which you shouldn’t have had to) you are NOT her parent, she probably doesn’t talk to your parents like this. You have to stop it at some point or else she will continue to be spoiled and disrespectful, she’s already crossing the line by telling you not to live your life bc SHE can’t do something.
The blackmail was definitely my last straw bc I was literally planning on sending her and my lil cousin money anyways since they were staying at my hotel then she tried to be greedy and ask for $35 at Taco Bell off all places. It's just hard be that's my only sister and I've always been responsible for her