None are “necessary”. And the answer is student dependent. SLE and NASS will give him a glimpse into each academy. Boys State will give him points on his applications.
He won’t be dinked for not attending SLE/NASS. He also won’t increase his chances at an appointment. *Most* do not attend either program. But, they can be an important piece of a students decision, should they feel they need exposure to either SA.
Boys State is a line item on the applications.
So, depending on your sons exposure to the SA’s, he may not need either summer program to help him.
I know that for NASS, and I would assume SLE is similar, you can request a change of assigned week if you have these conflicts. It’s not a guarantee, but it’s pretty common to want to attend both.