i'm very sorry jenny. we all know how serious cf is, no need to go there. i'd really like to encourage you to not think that she is deteriorating necessarily. if she was so healthy and suddenly got this sick-she could simply have a terrible virus or have a long running infection that hasn't been treated. i'm sure with a good cf team and strict care on her part, she will bounce back.
i try very much not to put the cart before the horse when dealing with things like this....see what you are dealing with, and then act from there.
hugs to you and your family