Ugh this is so so sad to read. I’m gonna get heat for this but say YTA (light) it absolutely sucks but it’s not your sister’s fault. It sounds like from your description she learned and tried to be self sufficient as best she could, being only 5-12yo and that you do love her and she is appreciative of you. You should not have had to parent her, being a child yourself, but as an older sister of two myself who did a lot of caretaking, I honestly cannot fathom not sucking it up and taking care of her in such a dire situation. Of course apply external pressure on CPS etc to resolve it. But would you really want her to end up in the system? You aren’t obligated in any way, but if we’re asking what’s the non-asshole thing to do? It’s to take her in :/ I ultimately hope an another adult or ur parents finally step up though.