So sad to hear that your sister is not able to come out of the suffering... Hearing to your history, it seems that your sister is suffering from BPAD... Being a chronic illness, BPAD requires regular follow up and prolonged medications...
But before we come to any decision, it's better to get her evaluated completely and if required changes in medication can be done. It's better to take her to psychiatrist immediately as she is actively suicidal.
Next Steps
take to psychiatrist immediately for in-person consultation... online consultation or counseling may not help
Health Tips
keep her in a safe environment... keep her under observation