tinaelise, sorry to hear of your Mom's situation. Don't be too hard on the medical team, though, as until you get into a problem, it is hard to know what you will find. As Gary mentioned, it is good that they stopped and came out to get a decision from you as to how to proceed. I had a similar experience as my surgery started, they found suspicious tissue and tried to get it biopsied and then complete the surgery but were unable to get the biopsy done in time and had to abort the surgery. I then rescheduled it and had to cancel it the morning of the surgery as my doctor threw his back out and couldn't do the surgery. Rescheduled again and he had to go out of town on an emergency. Rescheduled again and finally got it done. Hope your Mom doesn't have that type of experience as it is hard to get up for the event just to have it pushed off.
I was worst the last week of rad and first 3 weeks after. I think that is generally the experience most of us have. So your Mom should be relatively OK during Christmas. Hopefully, the treatments will reduce the tumor size and the surgery will be a lot easier and less tissue will have to be removed. Are they also giving her cisplatin chemo during rad? This is often done in concert with rad to assist in shrinking tumor size. Stick with her during the rad treatments as they were the hardest part of the treatment for me. She will need your support a lot. Also, when I was diagosed, they didn't know where the primary site was, only the lymph node that was enlarged. It was only after the tonsilectomy that the pathologist found the tumor that they were able to stage it accurately, so changes do occur during the treatment process. one thing about cancer is that we are all different and accurate predictions cannot be made in all ways for all cases. Sometimes you have to roll with the punches. Will continue praying for you and your Mom and the rest of the family.