"Ah, shit, Klaus." Diego knew how much Dave meant to Klaus. He'd been with him that say at the bar, when he'd seen the picture on the wall. He would never forget the look in Klaus' eyes, the way he'd been entranced by the image of his lost love. Diego knew just how deeply Klaus loved Dave because he'd seen it with his own eyes.
He didn't say he was sorry or anything like that. Words were inadequate. He knew because he'd felt nothing but annoyance and rage when someone said to him they were sorry about Patch. Sorry didn't cover it.
So instead of saying he was sorry or something equally pointless, he pulled Klaus into a hug. Diego was not a hugger. He didn't like to be touched, as a general rule. He made exceptions for his siblings, but he rarely initiated.