Can stress be one cause for having nightmares? depression?

It's been two years since Deepthi has moved to the states along with her husband, she often feels home sick. She is a home maker who mostly spend her time watching atleast one movie a day, cooking, cleaning the house, painting, gardening and a little bit of reading books. Though she had taken a few courses at the community college and was keeping herself busy, she decided to relax a bit for the summer staying at home.
Since her coming to the US, Deepthi has also developed some health issues like hypothyroidism, and some vitamin deficiencies which she was worried about and even asked me for some home remedies that could help her in improving the levels.
She often feels low on self esteem, lonely which makes her feel like she is having some psychological problem. I try cheering up in ways I can but lately she has even started having nightmares about losing some loved one or something evil happening around her. I have no clue what to do or how to help her.  She said she started watching this new series called 'the orange is a new black' which is about the life of a lady in the prison. And from that time, she even looks much stressed out. She is not willing to consult any kind of a psycartrist or any counselor regarding this issue as she thinks that might affect her personal and professional life.
Since I am the only person she has told this to other than her husband who is also worried and helpless about this situation, neither of us know how to help this girl.
If you have any suggestions please give.. This is equally stressful for me who is hearing to Deepthi about her troubles.