DS should pore over the prep partner websites, organize his questions, including cost share after scholarship applied, and get on the phone with the staff who oversee the SA prep program and develop his comparison spreadsheet. He can also call the USNA Foundation staff. They are ever-patient and understanding, completely dedicated to helping Foundation Scholars.
Your DS has been given a superb opportunity - commonly referred to as a golden ticket - because if he successfully completes prep, stays qualifed in all areas and obtains a nomination(s) next cycle, he is almost sure to be offers an appointment. USNA is essentially telling him “we like what we see, think you would benefit from a year of prep, and we’ll save a seat for you and wait for you to join Class of 2027.”
If he wants USNA, he should grab this and not look back. He will gain confidence and maturity in the time away from home and be laser-focused and well-prepared for USNA.
There are many successful prepsters in each incoming USNA class.