Delicate situation - Advice needed
So, i'm getting married in less than 6 weeks (so exciting!) I have 2 bridesmaids who are my 2 best friends. A few nights ago I went out with one of them who broke down and told me a lot of very personal issues that she has been going through and keeping to herself, she recently had a breakdown and has quite a lot of mental health issues. We had a huge heart to heart and decided it is too much pressure for her to be a bridesmaid- we agreed she should just come as a guest and enjoy herself. She feels terribly guilty and upset but knows it is for the best if she steps down as a bridesmaid. I love her and am happy with this decision and just to have 1 bridesmaid.
She hasn't told anyone else yet and doesn't want anyone to know about her problems. She is going to tell my other bridesmaid but needs a little time to build up the courage.
The problem is, everyone knows that she is a bridesmaid and I am concerned that people will jump to their own conclusions as to why she now isn't- obviously I don't want to put any more pressure on her / don't want to tell anyone about her problems but I also don't want people thinking we've fallen out / gossiping about her.
What do you think I should tell people? Any advice would be appreciated.