Mental illness. What should i do?

I understand your concern towards your sister. She seems to be suffering from few psychotic symptoms. However more clarity is needed regarding her problem to decide on severity of the condition. Don't worry it is not her fault, it is the hormonal fluctuations in her body which is taking a toll on her mental health. It is easily manageable with appropriate treatment, so that dysfunction due to the same can be reduced and her quality of life will improve. Some counselling sessions along with medical help might be useful for her. I would also be more than happy to help you with that if you are looking for online assistance. Discussions will be held confidential. You can directly consult with me through Practo as needed. Online chat consultation is available.