My sisters condition?

Well I live about 5 hours from home. I go to Kent State University for Clinical Psychology. Two months ago I got a phone call from my mother, saying my sister may be gowing through a psychological problem. Let me just say. We are questioning out religion, we were an agnostic family. Now im confused. My mother said my sister (12 years old (good kid never EVER had a problem with her)) was pulling her hair, screaming very loud, and punching walls, doors ect. Her hands began to bleed. My mother had taken her to psychiatrists, and they wanted her to go in for an MRI. Which they had done and found nothing. They ran more tests and found nothing. They believed my 12 years old sister to have schizophrenia. A week went by and she began to shake, she grabbed a steak kife and stabbed her hand. Again, she went to the ER. My parents were in the waiting room when i finally showed up. We are sitting there talking to my sisters doctor telling us they are giving her some psychological test. We then began to hear screaming, and different languages ( Finnish, Latin, and Aramaic). It was indeed my sister. I have never been so scared and shocked in my life to see my sister acting like that. She started to drink her own urine, and clawing at her eyes. Doctors told my mother recently, they have never seen a 12 year old act in such manor or even prefect these languages. They suggested to see an Exorcist. (The man/woman performing the exorcism) This was not just one doctor telling my parents, it was multiple. I am so confused. This is not a lie. She did not repeat any languages from the exorcism of emily rose either. Ive seen many of those movie and thought it was all BS. Now im really confused. Even the docs said that. What should we do. I am worrying every day about this. This is not funny. Weather she be the most crazy 12 years old out there speaking languages that doctors can understand but not me. Or be possessed. Either way. Do not joke about this. This could have been your daughter, sister, friend, or even you.