Thank you doesn't seem enough

Tonight was great, the boys and I went to Eisa and drummed until our hearts were content. We polished up the two routines we've been working on and started learning a third. Taiko drumming is so much fun, a good little work out and an amazing stress reliever.
Usually on the drive home we talk about the practice or other everyday happenings. Today was a little different. Both boys sat in back so my A driver wasn't there to keep me entertained. The boys played quietly in the backseat and left me to my thoughts.
I started thinking about Derrick's ever dwindling team, more specifically his sergeant that left yesterday to make his trek back to Okinawa. He'll be here just long enough to turn in his gear, check out of one unit, report back to his parent command then check out of the Marine Corps. His tour of duty is about to end.
I have so many feelings about this for many reasons, some more personal than others. I feel like I have a bond with him. This sergeant is the one who had Derrick's back the past ten months. He has kept him safe when I wasn't there to and because of him, I know it's because of him, Derrick is alive, and he is because of Derrick. They formed a bond, something bigger than anything I could equate and I'm sad that he's left Derrick's side. I'm sad that he's leaving the Corps, but I'm so excited for him and the prospects of the future.
I am worried for him too. He's leaving a brotherhood that isn't always perfect, but it's become his family. When he leaves is he going to get the support he needs? He's going from combat to the civilian world with little-to-no transition. I worry for him because he's one of Derrick's men. Even though I've only met him a handful of times, he's become family to me.
Derrick has said when he leaves this unit he won't look back. This deployment has been different then every other and not so much because the situations but because the unit, not that the situations aren't different this time also. The only person he'll walk forward with is this guy. That says so much about him. Derrick and his Marine.
So now that he'll be back on Okinawa in a matter of days I'm trying to find the words to thank him. Nothing seems enough. When Derrick comes home it's easy. I'm his wife and his best friend. For this man that I hardly know, I owe him so much. He was/is Derrick's friend, he kept him sane when things were absolutely chaotic and they've endured so much together. Bottom line is, he had his back more than anyone else. In this situation, under these circumstances this means the world. To me at least.
I hate that he has no family here on Okinawa. I don't know that his deployed command will do anything for his return, but the kids and I are in contact, or will be tomorrow, with his parent command (Derrick's parent command) to make sure that he doesn't come home to an empty barracks room. We are making him a welcome home banner and some cookies, but again, that just doesn't seem enough. How do you thank someone you hardly know, but who protected your heart from thousands of miles away?

Thank you Sergeant Borja. Thank you for being everything you are, and everything you were for Derrick, and for me. You were there for Derrick when I couldn't and you supported him in ways I could not. Forever I'll be grateful. I hope that life blesses you with only the best love, the best friendship and the best future. Semper Fidelis!