It may not take her six weeks to recover, as each person is completely different. Doctors would rather err by suggesting a longer recovery time than saying she could recover in three or four weeks because if she didn't recover that quickly then it's the other end of the question. Doctors would rather give you a possible answer to your question more than a probable answer to it. I hope that makes some sense, because when I reread it I'm not so sure about it. I think if the two of you were to read some of the different stories in the storyboard section, you will find patients with many different variations in their recovery time.
There's another woman on this site and she's 72 (her name is Jean) and about to have cystectomy and is also working at deciding which diversion she would feel most comfortable with. Of course it all depends on what they find when they get in there, it's possible they might have to alter plans according to pathology.
Best of luck to both of you, and keep rereading from this site, you can learn a great deal here. My prayers are with you both during your time of decision making and preparations for surgery.
Lou