parents are bad with my disabled sister

I live in a pretty problematic family & I feel like who its affecting it a lot is my sister. my sister is disabled & basically shes not physically disabled more so mentally, shes literally mentally like a 3 yo child (what the doctors have told) & she cant talk as well. both of my parents work as personal assistents for her & get money for it, but they dont actually work tho. my dad lives & has another job in another city now for 4 years & never worked with her in general, my mom gives her the basic needs but thats it, shes not trying to give her a normal life, shes 24/7 on her phone or watching tv & makes her always go to sleep & wake up super late. my sister is just existing there to give them money. none of them try to create a life for her & especially since she was done with the school thing she went to she lives this strange life, always closed at home & gets no attention. it disgusts me the way they are using her only for money, & I feel like I cant tell it to anyone. Im afraid that if I do it they will take her away to an institution & I havent heard the best things about these places. also my parents would kick me out or do other bad things to me & I cant live on my own yet, Im not economically stable. I feel horrible about this environment they have created around my sister I wish they were not so selfish. also Im afraid if I told this to anyone they would both say that Im lying & make up any shit about me to cover up what theyre (continue in comments)