My brother is preferred, what should I do?

In order to clarify what is always against me, my brother has such a disease (physical) and has supposedly other problems… I have 3 brothers and my one has a disease, but still he is always extreme with my parents preferred. Every evening I get bullied and scolded at dinner by all 3 brothers (sometimes during the day), although I hardly say anything and when I say to my brother that he should stop eating so I'll be right away from my parents " rebuked "and may not eat any more that day. My brother has today (when I was not there) z.b. Just taken my laptop out of my room and gambled on it and changed the password so I would not come in anymore. When I came back home, he stood in my door and said only that he has today recovered the laptop and that without that he has asked me or my parents. At the laptop, I did not get in and when I wanted to enter the password, I saw that my laptop is totally damaged and now has a graphics error. I just told my mother that my brother was on my laptop without asking and changed the password and that he should reset it, but my mother just said that it would not matter (because my brother supposedly has the password had forgotten then I had to reset my whole laptop). But that was not all, whenever my parents go shopping, they bring tons of sweets to my siblings and when I ask why I can't even get a bag of gummy bears, my parents say that I'm not hardworking enough (I'm aufm Gymnasium and do 3 times a week sports including school AG & my siblings are all on a junior high school and write all lower grades than me, none of them doing sports). Often my parents also tell me that I'm too fat, and therefore get nothing (I'm 13 and weigh 41 kg). I think my mother is even worse than my dad, then she's Really just about my brother. Or e.g. If he does not have to clear his dishes or help in the household (I have to table / cover and clean our bathrooms every weekend), if I leave a little board out, I will immediately be whistled back and snapped that I should behave myself and show them "a little more respect"… In addition, my mother always lets out her anger on me and sometimes beat me. It's not easy for me, and my brothers always begüddeln my sick brother and mean that I'm from a smoker family and not wanted (because I'm adopted). Sry for the long text, but I really do not remember what to do. And I do not want to lose my "family"…

Understand you well but your "mother" can't beat you or anything else and seriously you're not too fat at the weight (also had vile who called me fat but I ignored it better that way) with your brother I can't help but advise you to turn to your dad maybe he can get by