Smokey's face remains mostly stoic as Calen prattles on, even as he tries to drag his father into the mix. He doesn't say anything, doesn't make a move, just seemingly listening. As far as appearances go, Smokey looks as calm as can be. But beneath that stoic countenance is seething rage.
Calen had made a mistake bringing up Smokey's dad, and he wanted nothing more than to drive that gaunt, drunk face into the dirt in the moment Calen made his implication. But Smokey restrains himself, as he recalls a conversation his father had with him years ago.
"But Dad, he was lying! What was I supposed to do, let him get away with it?"
"That's not an excuse, and you know it. And because you reacted, they're going to say the same things again tomorrow, and the day after, and the day after that. You can't let them get to you like that, Smokey."
"So what was I supposed to do, then?! Let him keep talking?"
"Exactly. You knew they were lies, right? All you have to do is let him talk, and his own mouth will get him in trouble sooner or later."
At the time, that conversation didn't make any sense to him. Hell, part of him still disagrees in some regard, but right now that conversation seems strangely applicable. Calen hadn't outright lied, so much as avoided the question. Taking a moment to think about it, he'd probably hoped his father would be good enough bait to throw Smokey off the trail. Unfortunately for Calen, all that did was tip Smokey off that he needed to be on guard. And looking more closely at Calen's statement, his refusal to answer is all the more telling.
Smokey could call him out now, realistically speaking. By implying his father is killing faunus second-hand, Calen had opened a Pandora's Box of possibilities. For instance, following his logic, anyone who had used any form of Schnee dust had contributed to faunus murders. But, well, Prism has asked her question, so for now, Smokey will wait and listen for his response.