Hi Thomcat. I used to work with people with schizophrenia, schizo-affective disorder & bi-polar disorder. It was a long-term research study so we would see the same people many times over a number of years. We also interviewed and worked with their family members looking for genetic and other medical links to these diseases. I know it's not the same as having personal experience in your own family but I did get to know an awful lot about it.
Unfortunately, the answer to your last question is that as far as I know it doesn't get better, in the sense that she will never be "cured" and she will probably never be quite the same as she was before. She will probably always need to be on medication and even if she improves, stressful events in her life may make it worse again. That doesn't mean that with the right medication, support and other treatment she can't learn to control it and have a reasonable life. I did all this work in the states however so I'm not sure exactly what support should be available to her.
It's a very difficult, very complicated illness. Aside from the voices, she may have a "flat affect" which means she will have trouble expressing any kind of emotion. Her thoughts may be confused so words may not mean what she thinks they mean and she may have trouble expressing herself verbally or in writing. Difficulties with personal hygiene are actually a symptom of the illness as well.
I think the most worrying thing for those around her is the paranoia, if she thinks people are trying ot hurt her or out to get her in some way. But like I said, if she can get the right medication and the right support then she can learn to control the symptoms and more importantly gain some insight into her illness.
I'm sorry if that's all a bit scarey and not very helpful. Good luck with it.