There are people there they can talk to... but more they talk to each other, help each other, pull each other through the rough patches. Also, unless something is severly wrong they don't have the time to think about the mental stressers! They just need to do and react and maintain military bearing as much as possible. There are no couneslors to speak to when they are on a life & death mission, they are available afterwards but when the situation is going on, they don't have the time to stop and process. It's sort of the same thing in boot... they are moving at a fast pace and just doing, they process later. That's when the whole shipmate I need you-you need me attitude starts to develop. His shipmates will be some of the most important people in his life. This is just his first "ship"! There will be lots more.
A big help to him in dealing with it... letters, letters, letters from home! Make sure to write, even when they don't have time to read them, just knowing there is a letter is a great comfort! Just keep them upbeat, happy, let him know how the cat is, that the dog finally got neutered, the crazy old aunt burped the alphabet at Sunday dinner... don't focus on missing him, he knows, he misses you too!