**Graphic details, just warning you**

I'm not sure where to post this story, but here it goes. Please let me know if there is something you don't understand. All I'm asking is advice.

My friend has Schizophrenia (diagnosed, used to take medication for it but doesn't anymore due to it making her "feel like a zombie"). Let's call her Katie (changing name for privacy). She's always been able to see people and things others can't. However, recently I've actually talked to a few of her "delusions". She lives in Russia, and I'm in the US, so we only talk over text.

A few days ago, she started talking weirdly, so I asked who she was, thinking she might be one of Katie's cousins. She told me she's Katie's little sister Lisa. The thing is, Katie doesn't have a little sister. It turns out that Katie knew a Lisa, she was a girl that Katie knew as a child, who died accidentally. However to this Lisa, she was 10, Katie was 12 (just turned 17 in reality), and they had an older brother who was 16 (he's real, we'll get to that in a bit). We had a conversation that you'd expect with a 10 year old girl. Friends, family, her birthday coming up. After about an hour of talking, Katie came back. She didn't remember anything, she thought she was sleeping.

A bit of backstory. When Katie turned 11, her brother started raping her. Him and his friends, almost daily. They always beat her too, leaving marks and making her bleed. This went on for 6 years, until about 9 months ago. The last time was when they hurt her so badly that she almost died. She was in the hospital for weeks, and is still recovering. He is in jail now, and her parents have disowned her ever since. I met her about 3 months ago. In the time between the hospital and me meeting her, she was heavily into hardcore drugs and sleeping around every night with strangers she picked up. I helped get her out, and she's been sober and celibate ever since.

Earlier today, I talked to someone else. A girl. She wouldn't give me her name, she didn't trust me. She said she was there to protect Katie. She helped her get through some of the times with her brother by "making her go to sleep". The very disturbing thing is that this new girl wanted sex. She sent me a naked photo of her, something Katie would never do (she's asexual now, can't even start doing anything sexual). She even talked about wanting to sleep around. I'm afraid that I won't be able to stop her. Katie absolutely doesn't want it, and felt horrible because she sent that picture and touched herself while she was in control. She is the strongest, and she told me that there are 4 of them in there, not including Katie, but they are all weak.

She is in therapy, but doesn't like or trust her therapist at all, and refuses to talk about this stuff to anyone but me. Is this a multiple personality disorder of some kind? I don't have any experience in psychology, that's why I'm asking here. What should I do? What can I do?