Is It Ok to Unask a Bridesmaid if She Is Mentally Unwell?

Recently she has admitted herself to a rehab center for drug and alcohol abuse and depression and is moving to another province to be with her family. I am very concerned that although she said she would come back to be in the wedding that she wont be well enough to come back, that she will not be able to afford to come back becasue she is no longer working, or that she will act inappropriately if she does come back. The wedding is 3 months away and I cannot talk about this with her because she is very emotionally unstable and is trying 3 new drug therapies with her psychiatrist. She has also admitted to doing recreational drugs. I am so torn. I want a happy wedding but I don’t want to add to her mental instability by unasking. I had previously offered for her to step down due to her financial status but she was very angry with me so I bought her dress as a temporary loan. Please help me. I don’t know what to do for her mental health or my happiness.