Thanks for raising your concerns for your sister. It seems that your sister has been through significant distress in the recent time. You have mentioned her feeling insecure, being watched and monitored. It reflects on referential and paranoid thought processes. One needs to understand the circumstances and the backdrop in which her symptoms have emerged. In such circumstances, affected people feel threatened and insecure and find it difficult to differentiate between fantasy and reality. They may sound unreasonable and turn suspicious towards even the closest of family members.Your sister shall benefit from regular psychiatric reviews. It is also important to know whether she has been suffering from any co-morbid physical illness, or has been on steroids in the recent past before the onset of the mentioned symptoms and also whether there has been any past history of a similar illness. It shall help in her overall management. Regular compliance to treatment (incl psychiatric medication), social support, stress management and counseling shall help. Family needs to be careful in their interactions with her and avoid confrontations, critical comments or excessive display of warmth which may make her feel uncomfortable.