In my day, there was of course no Facebook, not even the Internet. Parents managed. I realize things are different today. FB and other "groups" can be an invaluable source of information and support. However . . .
Keep in mind a few things.
First, your child is now officially an adult. S/He needs to figure out how to solve problems. USNA has many, many support systems to help your child (now adult) navigate the process and solve problems. In a few short years, s/he will be leading young men and women and will be the one they look to for solutions to problems. Calling you every time won't be an option. Resist the temptation to get an answer from the FB parents' group that will solve all of their "problems."
Second, along those same lines . . . listen but don't try to fix things that you may not understand and really can't fix. I had the benefit of a dad who'd been USMC enlisted in the Pacific in WWII and later an officer. My complaints didn't get too far with him.
Seriously, he recognized: (1) he (and my mom) didn't always know the whole story, and (2) couldn't solve my problems, so (3) it was best to listen, be supportive, and let me sort it out. Which I inevitably did. Probably frustrating for them, but a lot better for me.
Third, USNA has been doing this for a LONG time, mostly without interference from parents. The Supe and Dant and their staffs are very senior officers who have been responsible for the lives of thousands of officers and enlisted in their careers. They really don't need advice from parents.
Fourth, DO NOT send letters or emails or call USNA leadership and don't sign onto letters or emails, etc. from parents' groups complaining about food, liberty and leave, mask policies, professors, the fact that USNA is interfering with some family event, etc. (Yes, parents do this -- a LOT). It can be embarrassing to your midshipman and isn't going to change anything (see #3 above). Trust in the system -- it really does work.
Bottom line: Parents' groups can be a wonderful thing or a very divisive, destructive thing. Tread wisely.