Hospital stays can be short or long despite being, on paper, for the same op. I was in for 7 days after my appendectomy as it was in a right old mess and I got peritonitis. My father was in and out in 24 hours as his was caught a lot sooner.
Plus, they will build in a "buffer" so if she is better sooner, they can get her home without fuss and if she is in for the full 2 weeks then no one will be surprised.
Whatever it is, she will be getting the best care possible so thats all that matters. I am sure an announcement will be made at some point so speculation is useless, and if there isnt an announcement then that means she wants people to mind their own business!