My very first flare was incredibly rapid. Fine one day to bleeding the next. Even now it seems like, when it goes downhill, it goes quickly.
Also, I was originally dx UC and treated that way for a year. Every scope since has shown Crohn's, with Crohn's symptoms such as fistula, etc. But, my biopsies and Prometheus test still show UC. If I have surgery, it will be a permanent ileostomy. That is because the rectal region is affected so much that they'd have to remove it.
I mention these things because if they docs are talking surgery for your daughter, maybe it's helpful to hear what other surgeons are recommending for severe IC patients.
Best wishes to your daughter!!! And to all of you.
BTW: has she tried Remicade?