He sighed and poured out care and understanding instead of words for a moment, "Obi, I never had a kid, but I was one once. No matter what a parent does or says, no matter how much they try ta protect their kids, one day those kids grow up. They make their own choices, an no matter how much a parent might tell 'em those choices are wrong, they do it anyway."

"I know ya love him, but it's not your fault what happened." It didn't matter if Obi-Wan ever believed him, McCoy believed what he said and he knew that would come through in his emotions. He just wanted to ease the man's pain. To make some of the agony go away.