Non trust and disease complaint. What.

My sister is constantly complaining that she has this disease and that disease. She was complaining of cancer because seeing symptoms online, we got everything checked but no issues. Then she's telling that parents are hiding something and not showing original reports. Now she's telling that she has TB and wants treatment for that. She's not trusting anyone. And constantly telling has this and that and wants treatment. My parents are fed up and constantly trying to make her understand but of no use. Parents are having patience and got all the tests done and seen doctor but still she isn't trusting the results of the reports and asking them for original. We are helpless. And don't know what to do. She has history of BPD. But I'm not sure if this is again BPD or what.