J.
My heart goes out to you it is a difficult situation.
I will share a couple things with you as both a psychotherapist and as someone who has had PTSD (not from military service but from other trauma in my life). I would highly recommend that your husband get some outside help. It is wonderful to have a supportive family that you can talk to but sometimes it is easier to share things with someone outside of your family.
I would recommend that he see a therapist that is trained in EMDR (Eye Movement Desensitization and Reprocessing). EMDR was given the highest level of recommendation (category for robust empirical support and demonstrated effectiveness) in the treatment of trauma by the VA.
I used EMDR to help me get through my PTSD and it helped trememdously. Through EMDR was able to recover from the PTSD. I have seen it used with others and greatly change their lives. You can find more info about EMDR at the EMDR institute http://www.emdr.com/
I know that you want t help your husband, the best thing that you can do is share your feelings with him and be as supportive and loving as you can. He needs your support and love right now.