I have been hospitalized twice over my OCD and depression. These are some of the things that were helpful or I think would have been helpful from a close friend:

• Be open with her about how concerned you are, this makes her feel loved and cared for.
• Discuss what her options are with her, thinking about solutions allows her to look forward to some things. An option might be having you contact her psychiatrist(ologist) and discussing with them some of the things you are concerned about. Making sure they are aware of the situation is crucial for her recovery.
  
• Reassure her a million time if you have to that those intrusive thoughts do not mean anything about her, nor represent her at all. We all have them, it's just about how much attention we pay to them. An idea that helped me was asking myself if the way that I am treating myself is how I would treat someone else in my situation, or my younger self.
  
• Consider doing some reading about it like The Man Who Couldn't Stop, and reassure her of some of the concepts they discuss in the book.

Thank you for taking care of her, you are a really good friend. I would also recommend taking some time for yourself, supporting a friend in need is not easy either and can take a toll on you. Because you want to continue providing her with good support, your mental state is also important.

By the way, what things will work really depend on your friend. I found those things helpful, but she might not. At the very least, maintaining an open dialogue with her is important, because it gives you an insight to how you can help her best.