Dear D.,
First of all, you are my hero!! (I was an ER nurse for 13 years. Since then, I've done peds home health and private duty peds for most of the past 13 years.)
Decades ago, my friend had scoliosis surgery when we were in high school. Since then, she's had 3 vaginal deliveries and raised a family. We've drifted apart, so I don't know of any recent repercussions. I assume arthritis might be an issue for her at this point.
The only other scoliosis surgery experience I've had was with a patient. The severity of her scoliosis required a trach/vent because her chest was dropping into her abdominal cavity. When I worked with her, she had had surgery and they were considering more, the details of which I don't recall. (You ain't seen nothin' until you've walked in on a 14 y/o on a vent jumping on the bed!)
You've had your 3 opinions, it sounds like your daughter has to go through with the surgery. Besides communication, I think pain management, toileting, nutrition/skin care, and prevention of infection would be your primary post-op considerations.
I'd be sure to get her out of the hospital ASAP because of MRSA risks, and/or I'd insist on changing her dressings myself while she's in the hospital to prevent cross-contamination. Let the staff do their necessary assessments, but you do the point contact. I worked with 2 different MRSA'd post-op lumbar wounds last year doing home health.
Pre-op, I'd prepare her for describing the 1-10 pain scale. Remember your vitamin C, zinc, and protein for wound healing and have her as nutritionally sound as possible going into it.
Don't forget to prepare her brother for his sister's hospitalization, recovery, and the ways in which he will be able to help.
Good luck!