Ask the doctor. The average stay could be 10 days to 2 weeks, but ask someone who knows her situation better than we do.
Afterthought--since she's not getting a neobladder it will probably be fewer days, but still, you should ask.
My wife was going to stay every night, but she ended up only staying the first night. So maybe, maybe not. Be flexible. She might need you to stay there. Be prepared to.
Absolutely. And she is going to need someone to stay more than the night. She won't be able to do anything by herself for awhile. She is going to need being taken care of coming out of the hospital like she took care of you when you were born. I couldn't get out of bed for a few days without help. When I made it to a chair I needed help getting out of it. Your mother is going to be very very weak and very very helpless.
Why wouldn't you tell him? That just makes sense that he is totally aware of every facet, whether it seems important to us or not.
If I seem rushed in my reply it's because I'm heading out to dinner and I didn't want you to have to wait hours for an answer.
Second afterthought--she might recover quickly and all that I said could be for naught. Be be prepared to stay and help her.
Best wishes for your mom and you,
Zach