Does anyone have experience with a parent with dementia having surgery?

My Mom is 91 with a prolapsed bladder - it looks like a ball between her legs. She also has dementia....The gynecologist/surgeon suggested a hysterectomy/tie up bladder/rectal repair as well. She is currently active and walking around. I worry the surgery will be too much for her to recover from. The prolapsed bladder is painful for her at times, but she is functioning....how in the world do I make a decision like this? I don't think having her bladder hanging outside her body is good either...what to do???