Also, tomnementh01, I think it was starkly clear throughout the episode that there wasn't much Castle could do. Cuddle her, comfort her, whatever..but it wasn't actually going to help her deal with it. But Esposito could, and he reached to her through him.Sometimes it is just about taking a back seat. Castle recognized that, and he did it. It's as simple as that! There is nothing inconceivable about it. He was just trying to give her some space!
Also, there is grief and then there is PTSD. If you actually do some research on the topic, you'll see that Castlehas actually done it pretty well. This is for everyone who is having issues about the PTSD thing. According to people who have been in her shoes, (http://www.leelofland.com/wordpress/?p=13586) her reactions were actually realistic. Also, no one's trying to make you laugh. PTSD isn't something to laugh about.
'she's in the wrong job.' The girl is suffering from a disorder! A very serious one at that. She was in pieces. Give her a break!