Hi elru,
Thank you for your caring nature.
It's appalling the cost of these foreign wars here at home, from limb loss to other disability to PTSD to . . .

.
I would encourage him to apply aggressively for any/all studies that he might be interested in as soon as possible. Can't hurt to try. Worst that will happen is he will receive a politely worded refusal letter. He already knows there's no instant cure, so that shouldn't take all the winds out of his sails if it were to happen. At least I hope.
Regarding your providing a session in nature. You know I'm kind of older and more conservative. I cannot help but advise extreme caution here. Your lack of training in this area is of concern to me. PTSD work can be unpredictable. Flashbacks can be sketch, to say the least.
Regardless of what you choose, I know it will be done with forethought and caring. It will most likely be a good thing.
Peace & Love