Have him read those heartfelt, sincere, best foot forward essays he wrote back to himself.
Ask him what his plan is to keep senioritis within reasonable boundaries, what will he absolutely not do (underage drinking, DUI, try drugs, excessive speed, flunk a class, let GPA drop - get him to say them out loud or even write out a plan). Have him identify a few things that would signal he’s starting to slack off and unacceptable consequences were occurring.
Ask him what his plan is if he loses any confirmed places at SA or ROTC.
I recall my parents simply asking me neutral questions, in an everyday tone, as if I were a thinking adult, no “you must or you should,” just asking me to think through various scenarios and making it clear I would be responsible for actions, consequences, secondary and tertiary fallout, and figuring it out all over again.
I recall doing One Very Stupid Thing (peer pressure, for once wanted to not be the introverted nerd girl), scaring myself, and then not putting a foot wrong the remainder of the year. I had worked too dang hard to land the college deals I had in play, and I realized I had ALL the power to piddle that away or not.
Thanks for the feedback! Maybe it's not senioritis, but more like burnout. Thankfully it's not risky behavior, more "I am so sick of the pressure"... like it's mile 22 of the marathon and those 4 more miles feel like 40. He's worked SO HARD....
Someone on this forum mentioned something that really resonated with me and I shared it with my now plebe son. They said something like: "Imagine getting that thin white envelope and thinking back that I wish I would have studied more or I wish I wouldn't have slacked in class". Now, instead of wishing, keep doing.
Of course, they said it much better than I just did
Don't get senioritis, especially if you are applying to a service academy. Admission is not guaranteed and you want to set yourself up for success if you are going to reapply the following year. In my senior year I continued to work hard until school was over and I was rewarded by increasing my GPA and my class rank due to everyone else slacking. I also managed to get some great letters of recommendation from my senior year teachers who knew that I worked hard to hopefully achieve my dream of attending the Naval Academy. In the end it is your son's decision to either work hard or slack off. But keep in mind that all of that hard work can be thrown out the window with a bad semester.