We've watched the same thing potentially happening with our DS (who has been also admitted to USCGA, but is waiting on USMA) this semester. Between the GF, the demands of 4 AP's, going to the gym, his buddies, his school and outside orchestra, yada, yada, yada, we thought there was huge potential for a crash in grades. Wife and I had made him a deal NOT to look in the HS parent's portal for the entire Senior year (and we've stuck to that, so far). So, were now waiting for him to "come clean" with his grades - which should be finalized today. Based upon what I've observed...I can't imagine he's done as well as he should have.
Conclusion: GOOD kids...TOUGH situations.