My Grandson Left For Navy Boot Camp
After a multitude of schools including jump and dive schools, he will be eventually assigned to either a Seal unit or a Marine Expeditionary unit.
I don't want to sound like a dick and I think it's a matter of you just being an AF guy and maybe what he's told you are just his goals but he/you can't really say where he'll end up.
Does he have a SEAL contract to go to BUD/S after boot camp? That's the only way he's going to get assigned to a SEAL team. He may become a clinical Corpsman and work for Group but he won't be on a Team.
As far as the Marines. He has to pass the Field Medical Training course and then he will be assigned where to go from there. He could end up at the hospital on Camp Pendleton, he could end up with MARDIV (Infantry).
If he wants to be a badass then he will want to shoot for actually becoming a SEAL and then he will be going to Army Special Forces 18D course (Special Forces Medic school) to become a SOCM (Special Operations Combat Medic).
Equally as badass is SARC (Special Amphibious Reconnaissance Corpsman), with the possibility of ending up with Recon or MARSOC (Marine Special Operations Command - think SEALs/Green Berets of the Marines) which is a Tier 2 SOCOM command. Tier 1 is CIA SAD, Delta, and NSW's DevGru so Tier 2 SOF is like guys movies are made of. Tier 1 is the guys you never hear about.
He's got a long road and it's best to just focus on what's next and not SEALs and Marine Expeditionary Force. He'll need to study a lot of medicine before he worries about kickin doors and snatching souls.
Hooyah!