I am sorry to hear about your SIL and hope that she has a swift recovery and is clear very soon.
http://www.fertilehope.org is a LIVESTRONG initiative and I know there are other programs out there, however if she is undergoing surgery and treatment in a matter of weeks I'm not sure what her options are for egg banking as that process can take several months (diagnostics and the actual procedure) if it is the same process as IVF. Hopefully someone with first hand experience can expand on her options at this point. I can only give my perspective on the actual cycling and donor egg options. Much luck to you all.