What makes people respond in different ways to things?

My sister is much younger than I am and she didn't suffer the abuse my older sister and I did. She tends to see something and panic, whereas I would stay level headed. I have witnessed and lived more trauma and violence than she has, so it takes more to rattle me. I would think that your boyfriend dealt with what he saw by drinking with his buddies. When we had a tragedy in the military, we let the guys who handled it, go out drinking. I guess that is how guys deal with some things. I am sorry you saw such a terrible thing. I think talking to someone would be a great help to you.