Contrary to what Mia texted Roy, Oliver had not asked her to set the table because he'd gotten dressed up on chili night. Though once he found out that she had, he would probably declare that Connor was his favorite, since Connor would be the only one to notice but not comment in any way. But Oliver saying that one of his kids was the favorite was a bit redundant, since they were all his favorite in their own way and no matter what happened, no matter what had happened, he loved them all fiercely. But sometimes they made him want to bang his head on a desk. Like now, when Mia pulled the classic 'evacuate the room for privacy' maneuver, completely misinterpreting the situation. Okay, well, maybe not, given the history that he and Dinah had and the fact that he still had feelings for her, which Mia knew (it was hard to keep stuff like that from her; she was astute, and Ollie didn't hide his feelings from his kids besides that). And yes, maybe he had dressed up because of Dinah, but that wasn't what he'd meant for this night to be about...
Dinah wasn't the only one who rolled her eyes at Mia. Oliver did as well. Catching that moment of mutual response, Oliver smiled despite himself. "Teenagers," he agreed. It took him a moment to respond to her question. The concern and genuine worry in her voice touched him. And why shouldn't she be? They were friends. Friends showed concern for one another. Except the look in her eye... "We're making it work," he said, "I—" The rest of what Oliver was going to say was cut off by the doorbell.
Opening the door, Ollie came face to face with Roy, his oldest (and adopted) son. It only took one look at his smirking face as he looked at Ollie for Ollie to surmise that he'd either been conversing with Mia somehow or that he agreed with her about the dressier-than-normal-for-chili-night outfit Ollie had chosen.
There was a quick, silent exchange between Ollie that took place entirely in looks: Don't go there, Roy. For the love of god, don't go there.