My elder sister is falsely accusing me of DV

Im 18 year old currently in 12th standard new delhi I've never posted on a message board before, so this is a completely new experience for me.  Please forgive any disjointedness in my summary. My big worry, of course, is to discover that I'm alone in this particular experience. Maybe she's psychotic. But, she seems to be able to maintain relationships when she wants them, which leads me to believe that she's not psychotic. Anyway, that's neither here nor there. Let me explain the whole summary. My dad was a central govt employee and died last year due to covid, difference between my elder sister's age and mine is 10 years, my mom is a fashion designer. she doesn't devote most of her time to family but when me and my sister are in a conflict she tries to maintain peace. My sister would jump between loving moments and wild irrational rage. I remember when i was 7 years old she used to slap me everyday after coming home back from school and my mom used to scold her for this behavior after she stopped doing for sometime, after that she started doing that again. after 5-6 years she's distanced herself from family. She dated a guy X she liked him. But after a year she left him for another guy Y and after 2 years of dating Y, Y left her. Now she lives with us but her mind is very unstable she lives in confusion sometimes she tries to love me and my mom otherwise she rages irrationally both of us she is working in National museum because she wasn't able to handle stress in her last job in a Private company. She pushes her emotional trauma on her family most of the time. She tries to scare me by saying i am going to file complaint to police for domestic violence and you will be behind bars. Once she tried doing suicide by trying to drink poison all me and my mom's fault was we tried stopping her from drinking it now she's saying that she is going to file a DV case against me and demanding a big lumpsum amount im just 18 and now i have no idea what should i do.