How to help friend

My (27F) friend (28F) had a baby 3 weeks ago. She is really having a hard time. She is currently being treated for PPD with medication. She told me she has been hearing things that aren’t really there (didn’t specify if it was voices or not). I asked if she planned to talk to her doctor about it and she isn’t sure. How can I best support her? I know I can’t force her to talk with her doctor, but I am so worried about her. She is INSANELY sleep deprived. I live on the opposite side of the country or I would go help her. I’ve been there to listen, but I know that only helps so much. She does have a counselor and supportive husband, so that gives me some comfort that she isn’t completely alone in this.