lil_penguin, may I ask if you are a healthcare professional or someone who is looking to become one, or are you here to get answers to your questions? I'm not trying to be rude, but you need to understand the purpose of this website. One of the most important things about it is that we cannot give out medical advice, at all. I know you are probably just trying to get an idea of what will happen, but without knowing all that has been done, and what they plan to do, it's nearly impossible to tell you these things.
Please don't post that info, we cannot give medical advice anyway, and it is a privacy issue as well.
What we can tell you is that he will have an IV, likely have a little oxygen at some point, probably a mask-type apparatus since they will be working on reconstruction of his nose, and will have a soft catheter in his bladder for a few hours after surgery. The fact that he couldn't urinate after surgery the first time is NOT a cause for alarm for you. Many people have problems with inability to urinate after surgery, it is a side effect of the drugs that are given to keep him comfortable. If he's booked to stay only 23 hours it doesn't sound like something that is deep and involved, but again, I canot tell you that for sure. Just please realize that he will be getting good care from the doctors and nurses and techs that is their job. Your job (and it is a very important one) is to be there and be calming and supportive to him.
Sometimes knowing too much can actually be a bad thing. Many times when myself of a loved one has a medical problem I wish that I was not a nurse.
Best wishes for a very speedy recovery for him and good luck to you in getting through it. I know it is tough to want to be able to fix it and you can't. Try to relax if you can.
One piece of advice, if your BF wants you to be able to talk to the doctors about this, have him write a note saying that it is okay for his healthcare professionals (use that phrase, it covers most people, MD, RN, LPN, etc) to discuss his condition with you (write your name out), then have him sign and date it.