I don't think I fully understand your pain, but there are those on FR who do. My earlier words (if they convince you) stand. Marines especially, but all American troops who die or receive wounds in the line of duty are a permanent part of our country's story.
We would not exist as a nation without them and their sacrifices. We all owe our lives to them, every one.
The history of free nations is that of warfare. From the first democracy in Greece until today it has not been much different. We do not sacrifice our troops, but some do have to pay the ultimate price.
If the grief is too much for you or your friend, feel free to start a prayer thread, if that may comfort either of you.
Thank God for all of our heroes and their loved ones! Thank you for the tribute to them.