my sisters mental health ruined my life

hi guys I have no one to go to I can only confide here . My sister has schizophrenia and for as long as I can remember has always been sporadic and aggressive towards my family in 'episodes'. This year in April she had an episode where she tried to kill herself and my brother had to push her against the bed to restrain her while we called police. my mom kept fighting for her to get out of the mental health 2 days into the 2 week treatment and I was begging her not to because she needed to be there. The psychiatrists actually end up being the one to sign her off early and I was so mad. The next day in the evening she went for a walk while we were doing laundry and came back with a bloody mouth. Apparently she bit someone because they refused to give her sodas for free (he was a long time friend of hers and usually did), and called the police. my mom bonded her out even though my siblings and I begged her not to. Charges ended up being dropped because again, this was a longtime friend of hers. My sister was alright for awhile until literally just tonight she argued with my older brother over him refusing to give her a ps vita since it was his property. She got angry and tried to force herself in the room. To prove a point he threw it on the ground saying "now no one gets it. Stop complaining" and she got angry and threatened to defile his room and his car. Her yelling terrified me and I had a panic attack and she started yelling at me saying I treat her like shit (I avoid her and respond indifferently to avoid stuff like this) and it escalated into something physical between my older brother and her. Now the police is here and I'm so mad and sad at everything. I'm 18. We have a 15 year old in the house. I'm scared he's gonna be taken away I love my younger brother so much and I don't want him in a foster system. I hate my sister and my mom so much. I don't know what to do. I feel fucking ashamed for hating them but what can I do. My mom enables her behavior by letting my sister do this shit simply by defending her and getting her out of mental wards because she claims my sister is scared there