Oh. how terrible. I don't really have any advice but just wanted to say I too would feel dreadful if my lovely brother was in that situation. Have you tried flower remedies, I take them and they seem to work for me. You can get them from Boots & H&Barratt and they usually have a leaflet explaining which one to take for which emotional state.
Hi Take one day at a time while he is there, my only son is just finishing a tour out there and will be home at the end of the month, he had already done three tours in Iraq and I was a mess every time he went, we have to be strong for them while they are there, I am very proud of my son and cant wait to see him when he gets home, you be the same for your brother and youll get through it. I take my hat off to every serving person out there not just my son; write to him as often as you can as he will love to hear all the family news, he wont be able to tell you much about what he is doing so I learned not to ask to many questions other than was he okay and to tell him I love him very much. Good luck its hard but you can do it for him
My DH has been twice in the last 2 years and he loved getting letters, sweets and blueys from his sister. Much as he loved our letters/eblueys, he loved hers too because they tended to be more lighthearted than mine and the kids. Although it might seem to go slow to start with, you'll soon be corssing off the days 'til he flies home. Don't worry if he doesn't email/call for a few days at a time but there are often phone/email blackouts for security, say if a VIP visits. It's not always because someone has been injured. The company 'boxhappy.com' send excellent boxes of retro sweets/ pressies such as bears with messages on etc at BFPO prices I think.