My sister, that I lived with on weekends to escape my abusive alcoholic father, was eventually diagnosed paranoid schizophrenic. Very stressful, I understand. We mistakenly thought she was just drunk most of the time because she did drink but it was much more than that. It took decades to get her committed and cared for in a group home, where she continues to slowly go downhill. It is very similar to alcoholic behavior and consequences to those around her.
Awareness is key to healing. Continue your search to find support. It also helps to know that she is safe finally.