What was the US marine corps like during the 2nd battle of Fallujah, Iraq?

My best friend served during this time and he died in a car accident 2 years after he came back. I think about him a lot around this time of year (when he passed) and always wondered what it was like for him.

It messed him up a bit but he kept it together very well and I was proud of him. His mom knew how close we were and gave me his tags after the funeral. I don't feel right wearing them because I was never in the military so I hung them in my bathroom where I see it every morning