@Jerelyn1 The mother can't book for her sons. 3rd party bookings are against Airbnb Terms of Service . If you accept a 3rd party booking, Airbnb will not have your back on anything.
I would respond like this "Hi XX- Thanks for your Inquiry. You may not be aware, but 3rd party bookings are against Airbnb's Terms of Service. Accepting a 3rd party booking would void my insurance. If your son and his friends are at least 18 years of age, they can open their own Airbnb accounts and book for themselves."
I'd venture a guess that these boys are under 18. And anyone who needs their mommy to book for them isn't mature enough to travel on their own, IMO. Or the boys had an airbnb account and got banned for trashing a place. Shame on Mommy, the enabler.
P.S. you don't need to either pre-approve or Decline and Inquiry. Just messaging back within 24 hours is sufficient. After that, ignore any proddings you get from Airbnb to Pre-approve.