please help me and answer this question!

Life hasn't been easy for my parents because when me and my sister was growing up, we played up bad! ( which I feel bad about now I am older and have realised) . But hermione (3rd oldest) didn't play up at school like me and Emily did but she plays up really bad at home. Hits people, screams until she gets her own way, doesn't do anything to help around the house when somebody asks and also speaks to everyone like abssolute dirt! But mum and dad seem to give her everything she wants when she wants, never punishes her, always praises her, puts me and my sisters down saying you should be more like hermione and honestly favourtisies her over the rest of us ( well i think). ****Do you think it sounds like they do favourties my sister hermione over the rest of us? **** 

Mum and dad said they treat her like that because she doesn't give them any hassle does it sound like she's a angle this it what I don't understand I have tried telling my parents how I feel but they won't listen what do you think !! Please someone help me !!