/dep/ - Depression

I want to rant about a certain succubus – my 8 year old sister.
She looks hopeless to me. She has extremely bad behavior in general (ten times worse than of a toddler half her age), she's shameless and degenerate (doesn't mind walking around the house in nothing but her underwear just because "it's hot", likes slutty clothes and behaves in slutty ways; doesn't mind talking about gross things such as literal shit, often opens the bathroom's door when others are inside as a "joke", etc), she's spoiled, she's addicted to YouTube and stupid phone "games", and while she behaves like a toddler in some areas at the same time she also displays manipulative and psychopathic evil succubus traits that wouldn't manifest at this age yet, etc.
Although I start my day in the afternoon (since I go to bed closer to dawn), I'm temporarily woken up every day at around 8 or 9 AM which is when she wakes up to go to school, and I always hear my mother screaming at my sister, and my sister also screaming back. Recently I even heard my mother have a breakdown because of her behavior (not the first time it happened).
At her best, she's just noisy and hyperactive and can't shut up and stop bothering others, and if I point that out my parents say that she's "just lively" or "just playing around" or "just a kid". Also they don't let me hit her back if she hits me (because they say it will somehow make her docile and accepting of abuse in the future).
I spent years hoping that as she grows she'll become better behaved, but if anything it looks like she's only degrading, so at this point I realized that she's a genetic failure, and her non-inherent negative traits have been solidified by now (by my parents spoiling her, etc) and are being constantly strengthened and thus should be nearly impossible to reverse. If you deny her anything (like jewtube, mobile "games", etc), she'll start screaming and behaving like a crazed beast (especially bad since I live in an apartment – what are the neighbors led to think when they hear it?), so she can't be "unspoiled" unless she was left in a schizo padded room for a week. By the way, she's not low IQ per se and if anything she seems smarter than average (although she behaves worse than a nigger monkey with 30 IQ), and she has decent looks, and of course, my mother is always complimenting her on those things and boosting her ego.
When she was conceived my mother was close to 40 already, and while that didn't make her retarded or ugly/deformed as I described above, that must've fucked up her brain in other ways resulting in her horrendous personality and behavior. Funnily enough my mother refused to take anxiety meds when she was pregnant with her because she said it would make her "slow" – alas, that would have been much better than her being a hyperactive demon.
I wouldn't say that I had an abusive household or anything like that, but when I was a kid, my mother sometimes beat and insulted me, and today she's constantly apologizing about it to me. But she holds back on this for my sister and just screams at her whenever she doesn't behave well (which of course is multiple times a day). Personally, I think that it would do good for my sister to be beaten and insulted. She really deserves it, and it could straighten her up a little and make her modest and tame. Whatever psychological scars that could leave doesn't compare to the nuisance that she is to others.
I still hope that she'll get a little better in the coming years, but it's a weak hope. And if anything I think that her teenage years is when the demonic flower will blossom – her sexuality will awaken and I can envision that she'll become a completely defiled whore, along with drama related to "relationships", unwanted pregnancies, etc. I should also mention that my mother is "religious" and goes to church every other Sunday with my brother (didn't mention him so far, he's fine, also he's in his early teenage years) and my sister (my father and I used to go too but we lost interest, but I still pretend to vaguely believe in the religion to not cause drama with my mother). It would be good if religion could prevent sexual degeneracy from my sister's part, however my sister doesn't have the good qualities of a Christian at all (she behaves like fucking satan), and if anything she likes to boast about how she believes in God and goes to church unlike my father and me, or whatever. Therefore I doubt that the religion could save her hymen, or at most, she would do the classic "loophole" of avoiding vaginal intercourse for "Christian" virtue signaling while being an anal slut, or whatever.
I ranted a bit, fellow wizzies, but it's really bleak. Do you have any advice or suggestions? Is this situation out of my control, or is there anything that I can do?