Yes. They will again reapply for the academy at prep school. They will have to retake the PFE again. They can be taped if weight is off.
If you get injured at prep school you can be deferred. You may have to get cleared. For example DD got Pneumonia at prep school. She was issued and inhaler. She had to get it cleared. She was temp DQ’d. If you show up to CGAS and they determine you have a prexisting condition they will revoke the appointment. No difference from Reg Day 1.