The Few, The Proud, The US Navy Base gate guards!!

Sorry, that was old Navy joke. Way back when, it seemed the only Marines we saw were gate guards at each base.
The Marines always had the best looking uniforms and I still think it's the least pc of all the Armed Services.

He will make you proud and best wishes to him in this new chapter in his life.

Be sure to encourage him to push himself when it comes to opportunities while serving and not just sit back thinking, "I'm just an E-4, I'll let someone else worry about that". The more he gives, the more they will give back. And that's from my own personal experience, which still rewards me today (and it's been 23+ years since I was honorably discharged from the Nuke Navy).