There is truth to the jaw thing being a matter of timeliness. Depending on what they need to do.
My son needed a herbst device to help extend his lower jaw, due to overbite. It was for about a year-18 months that he wore that. He wore the braces for about 2 years. (simultaneously)
Retainers after removal of hardware is standard practice today, along with, in most cases, a permanently affixed lower retainer.
The jaw thing may be urgent due to growth spurts/patterns. If they can catch your son in his large growth spurt window, it speeds the process along and makes it easier. If they don't catch it early enough, it may not achieve what is needed (due to slowing of growth) and surgery might be needed at some subsequent point. My son had the herbst installed at age 14 or 15, and achieved what was needed. He had not yet hit the fullest of his growth spurt at 14. If your son is in the middle of his, that would be something to consider.
(A Herbst device is essentially "headgear" that is fitted entirely inside the mouth)
Neither of my kids had palate expanders. That doesn't mean yours don't need them. I don't know if they do or not. Our orthodontist is in his 40s. Not brand new, not old school. We did pull a few of daughter's teeth when she was 10 or 11 (she hadn't lost her baby teeth and the permanent ones underneath were growing sideways rather than up... so making space encouraged them to find the path of least resistance). She still has one baby molar left, but had her braces installed last week (she's 13 now). The removal of the incisors was successful and the permanent teeth turned up and came in where they should have.
The rest of her work will be done with the braces themselves, no additional devices. Both of their treatments cost in the neighborhood of $5,000, including retainers after treatment. As their office explained it, a large part of the fees are simply due to office time. They are scheduled for visits regularly to make adjustments, and follow up (and pre-care for our daughter who has been being monitored for over 2 years without any actual orthodontic treatment, other than x-rays and monitoring how her sideways teeth are coming in, whether we needed to pull others, when she would be ready for braces, etc), and any minor repairs that may be needed, along with xrays, etc.
What does your regular dentist say about the proposed treatments? Normally, even though they are not orthodontists, they might have some general idea of if something sounds out of line.
-- ETA--
If you think your *medical* insurance will cover orthodontia, don't count on it. We do have a supplemental dental policy, and that still only covers up to 70%, but has a maximum benefit that is lower than half the overall costs. Our medical policy (which is pretty high end) covers NONE.
https://www.aaoinfo.org/news/2014/11/affordable-care-act-...