Wow that sounds like a tough situation. I think that its great that you sought out others to help you to convince your friend not to join up. What I would say is that there are a couple main things that suggest that it is not in his interest to do so. The first one is that he may get fucked up by the experience. Close to 1/5 of returning vets (300,000) come home with Post Tramatic Stress Disorder or major depression according to a study done by RAND. This is why the number of veteran suicides is near or higher than the casualty count. "On average, 18 veterans commit suicide in the U.S. every day, and four of those are veterans of the Iraq and Afghanistan wars." Not only that but there is a conscious effort to deny health benefits that would help this problem because the funding is so weak. This article talks more about it.
http://socialistworker.org/2008/07/04/hidden-casualties
The education benefits are not that great. They only cover part of the cost and you have to pay the military some part of the amount to actually get them. Its so screwed because the military actually MAKES MONEY from this because many vets don't use the benefits. One women I met was going to a community college and she had to work anyway to pay tuition and rent. On top of that she had PTSD and she eventually dropped out.
Iraq Veterans Against the War has information and video testimony about the reality of this war and the effect it has on soldiers and iraqis based on personal experience.
http://ivaw.org/publicdocuments/TruthAboutWhatRecruitersPromise.pdf http://ivaw.org/wintersoldier/testimony
A lot of testimony is rather jarring...
I think it should just be mentioned that the government does not give a shit about the soldiers it sends to war. They are just used up and thrown away, exploited for the imperial aims of the US ruling class.
The last thing I want to say is that very unfortunately your friends experience is not unique. Far too many folks have very poor life prospects through no fault of their own and this includes college grads. By many measures the standard of living for millions of people is the lowest today that it has ever been and the prospects for our generation are just as grim. There is nothing any individual can do to resolve this complete collapse of the American Dream. What we need is collective action.
Alongside the worsening situation we have a leftward shifting consciousness in a significant section of the population. A majority of people want the progressive reforms of single payer healthcare and other government services, and end to the war, etc and our generation in particular is the most in support of this change.
http://socialistworker.org/2008/06/18/generation-debt
What remains to be seem is if people figure out is that this change can only come if power is forced to concede concessions by a mass movement of the people. We need to build such a movement today that can end the war and force the government to spend those resources on "jobs and education, not for war and occupation" If you are not an antiwar activist yet you should seriously consider it.