Re: What my husband suffers from
Insist he sees a doctor. No, not nag-->INSIST! Put your foot down. "This is how it is and what you're going to do. Period. I'm worried for you, you are worried for yourself but you aren't acting on it. Now you're going to because it's the RIGHT THING TO DO." Tell him you will go with him even if it means only staying in the waiting room.
His sleeplessness should be addressed ASAP and can be done with Ambien. Getting good sleep for several nights in a row will help alleviate the edginess and stress which helps people think more rationally. It will kill the nightmares for a bit too.
But, nightmares are just the unconscious mind trying to resolve internal conscious stresses. He just needs to understand that they aren't something to fight or fret over, but a result of his mind clearing out a bunch of junk. Sometimes it makes sense, sometimes it doesn't, and sometimes it's just triggered by too much spicy food.
If he wants to forget his past in the service, let him. He won't ever really completely forget, but he needs to see it for what it is: one chapter in the story book of his life. And it's a chapter that is for the most part done. He only needs to close it and begin writing new ones for himself now.