Welcome,
That is one of the rarest cancers out there. I can't answer why they would wait so long to start treatment. If it were me, I would be asking why no one has suggested a radical cystectomy (RC). This is a very aggressive and dangerous cancer.
Here is a quote from a study done in Mexico on 2007.
The management of such tumors has not been standardized, due to their low incidence.
In any case, most published studies point to radical cystectomy as the treatment of choice, generally followed by chemotherapy or radiotherapy. However, the benefit of complementary therapy with respect to surgery alone, in terms of the reduction in relapse risk and improved global patient survival, is not clear.
Here is another link stating the same:
www.ncbi.nlm.nih.gov/pmc/articles/PMC2695712/
I think she should find a qualified cancer treatment facility, to get another opinion.
What clinic is she at now? If we know where you are, we can try and make a referral to a know good clinic near you.
Mark