<human>: My [37f] sister moved in 3 months ago along with her [12f] daughter and it seems like she's planning on staying for a while. She moved out of her boyfriend's house for whatever reason and recently I found out that she has done this a lot. The boyfriend would kick her out (no one can really stand her character) and she would go back to her mother's apartment, only to go back after some months. They would still be dating. 

Now that her mother is living with her son, my half sister went back home to daddy along with her daughter. Everyone was saying this time they were done for good but thats not the truth. I think its childish to go back home so often, and it seems like she is not embarrassed at all about making these huge scenes so often. Now that she is saving all her money from not paying for rent and food shes going on all these vacations and setting up more for after she comes back. She has never liked me and now no longer speaks to me. 

My dad thinks shes making stupid decisions but isn't telling her she needs to grow up. No one else in the house wants her here, its me, my little sister and my mother against my dad. I'm getting fed up with it and I'm ready to tell my dad that if she doesn't kick her out I'm moving out. I'm a full time student and not working at the moment but I have some savings and willing to leave because I can't handle it anymore. Im getting my real estate sales license on monday and Im waiting for that to begin working again.

Any advice

Condense the text into a few key points
<bot>: half sister moved in and instead of saving money to find her own place, she's spending it on useless vacations with her boyfriend who she had allegedly broken up with. Should I move out?