Oliver, by virtue of already looking grave and delivering bad news, can't look much more somber.

He can look surprised, dismayed, then somber, however, at the news of Mel's sister. He touches the white flame tattoo of on his forehead.

"How horrible," he murmurs. Then, distractedly: "I'm afraid I didn't ask for details. Valerie Bell would know more-- her sister." A small, sad shake of his head. "It was a car accident?"

It's the best Oliver can guess on what little information he has.