I also didn't like the way Castle only seemed affected by his mother's tragedy in the scenes where he was with her. Beckett was even surprised to see Castle interviewing the reality-show guy when she expected him to be home dealing with the family crisis, and he seemed totally unfazed by it.
Castle is a pretty private man, despite appearances, and he definitely doesn't like looking vulnerable to Beckett. He played things pretty close to the vest when he was hurt by Beckett dating Sam Anders last year (though this is a whole other level of emotional turmoil, obviously). In fact, him jumping right into the interrogation without Beckett (and without meeting her first in the morning) was extremely different from his routine, and was probably one part throwing himself into work to take his mind off things and one part hitting the ground running so Beckett wouldn't have the chance to ask him about what happened.
On a completely different note, I appreciated the tidbit at the end about his name. I'd wondered why he had a different last name than his mom. My first assumption was that his father was Mr. Castle, and he was one of Martha's ex-husbands, but then they said that Castle had never met his father and had no idea who he was, so I was just stymied. I wonder if any of his books were published under Richard Rogers. Of course, given his age and his twenty-plus bestsellers, he would've had to have been publishing practically since he was a teenager, so it's not unlikely.