Seriously?

Roman and Percy had followed Penny and his younger self to this restaurant—which was still one of his favorites—and made sure to be seated at a table within earshot so they could tell what was going on. He was confused by what he was seeing though. 

"…is she interrogating him?"

Percy didn't answer right away and when he did, it wasn't related to the question he asked at all. "I remember that day. I should have asked her if she was okay. I should have been a better brother to her."

Ah. He was still stuck on the story she told about the two of them when they were kids. It didn't seem like Penny minded what he said though; she seemed to find it funny. 

Her smile was definitely a nostalgic one. It was obvious that she loved her brother even though he was a bit odd. He certainly became much more considerate later since he was super overprotective the one time they officially met in his original timeline.