I don't think so. But I understand how you feel. No one, even the most patriotic, wants to see a loved one go off to war.
I have a nephew who did exactly what your BIL wants to do. He is not a young man and he has already served his country honorably, but he reenlisted and is now stationed in Balad, leaving a wife and a baby girl at home. It was something he felt he had to do. We are very proud of him and we all supported his decision to go, but I think it is safe to say that everyone in his family hoped that, at the last minute, he would change his mind.
I understand, it's a difficult thing you are dealing with. God bless you and your BIL.