please help!

How can we support or help my SIL who in the past said she felt like she had bipolar( self diagnosed), depression and severe paranoia. She was admitted last year but she never followed up. She believed people were watching her, monitoring her phone and that her professor blocked her from getting a job. She thinks her brother is in the military or a secret govt. agency. 
As of today, she doesn't have motivation to apply for jobs, she has a masters degree but doesn't want to work. She suddenly said she wants to be a pilot but we know she's scared of height. She hasn't done any research on what she needs to do to become one. But she believes if she eats well, she can become one. 
There's family history of mental health (grandma and mom) but when we spoke to her about seeking help today, she denies having any reason to seek counseling. 
We know this isn't her true self and we don't know what to do to help her. 
Please help!