I got a chance today to borrow five minutes from my senior pastor and go over something that's been on my heart. I've known for a long time that we're commanded to be praying for our enemies, but that becomes a whole lot more real when your "enemy" isn't a jerk at school but someone who's shooting at your brother. Ken spent much of his 20s in the Air Force, so I knew his answer would come not only from a sound understanding of Scripture but also from practical experience.
He explained that, beneath all the politics and strategy, Tim and his fellow Marines are in Afghanistan to suppress evil, and that God is in the business of defending the defenseless. So we can pray that God would change the hearts of the Taliban fighters or that He would take away their capacity to do evil (for instance, defeat in battle). This is a biblical way of praying for our enemies.
We touched on Nehemiah, too, which is the sermon series we're in, and there's an appropriate parallel - just as the Israelites rebuilding Jerusalem had a trowel in one hand and a sword in the other (Nehemiah 4:17), so does Tim have his camera in one hand and his rifle in the other.
So, in addition to praying that God would protect Tim and his unit and that He'd draw him closer to Himself in this experience, we can also be praying for the Taliban fighters on the other side. Easier said than done, I know, but I know that God does work when we pray, even when we don't fully understand it.
I think that's pretty great advice.