You are now in the waiting stage. Fun, isn't it

. Most SA candidates hear by April. Your son can update his file with any new SAT/ACT scores, winter athletic accomplishments, any new extracurricular activities, new leadership positions, etc. We were told the same thing last year - my son had nothing new to add, so all we had to do was wait once the app was in and the nominations were in place.
Has he visited the USMMA? Now would be a good time to do that if he has not.
Here's what we did while my son was waiting:
-explored the SA websites and the military websites. This activity will use up a lot of time

-reread all the academy and ROTC materials sent to him
-spent time visiting his backup schools and learning all about them.
-found this forum and read everything
-took long walks that included going by the mailbox several times
-started watching the military channel

-started watching cadet and midshipmen youtube videos
-read books suggested on this forum - that led me to many others about the military. My son read a few books, too.
This is the time of year many are waiting. Best wishes and congratulations to your son for his accomplishments!!!