Sister with Psychosis

First time poster. A long post.

My sister is 32 and lives at home with my mum & dad. She suffered her first episode of psychosis at 21 to a point where my parents did not feel safe and called the emergency services (I was living out of home at this stage) and she was hospitalised for a period of time. Since then it has been a long time for recovery. She slowly progressed from being extremely abusive phsycially and verbally to my parents and I and many hallucinations/paranoia of a sexual nature, or just general paranoia. She was under medication and it has taken approxiamtely 10 years to stabilise to a point early this year where she was doing well and had full time work.

Recently she has developed signs again of another onset of pyschosis. She is not nearly as bad as she was last time, and is still attending work but we don't know what her behavious is like there. She has started with paranoia and minor verbal abuse to my parents. I do not live at home anymore. We have discovered she has stopped taking her meds for at least 1 month now. She has taken a sharp turn in the past week.

I can see that my parents are exhausted and stressed and are basically a sounding board to her horrible words. I have come over several times now and checked in with her. She says she is fine, but will often rant on about one thing or another. I directly asked if she has taken her medication, she said she had. We checked and she had not. I told her I though she needed to see her psychiatrist as she does not seem well. She disagrees.

How do I convince her she needs to see the psychiatrist, or take her medication, if she does believe it. She doesn't remember her most recent severe verbal attack on my parents. Is this something i can tell her she did, as a way to convince her she needs to check in with the psychiatrist?

Thank you for any advice.