Frank frowned slightly as his father corrected himself, but he couldn't blame him. Neville had no way of knowing what his son was up to. It was just lucky Ace wasn't home, yet, to overhear and make a big deal of it. Or, worse yet, demand that he show her how it worked. Frank wasn't sure she'd want him to, but he already knew he wouldn't involve her in it. Not yet, anyway.
When the request was made, Frank just nodded, and moved to sit down on one of the chairs at the kitchen table. If he was going to get into this, he wanted them both sitting down in the hopes that it wouldn't escalate. Not too much, anyway.
"So," he began slowly. "You remember how me and Luke Avery were mates at the start of school? He used to joke about how uncanny it was when I mimicked people. I treated it like a joke, but he mentioned it to his dad and... the summer after third year, they asked me for help. Him and his family, I mean. There was this first year, Erik. From one of the more, uh, ... damaging and dangerous pureblood families." His mouth thinned into a grim line. "Y'know."
Frank shook his head, trying to push away the thoughts of the grandparents on his father's side. That was only partially relevant.
"Point is, Luke said he needed my help, and it didn't seem illegal or anything. He said the Averys were breaking the law, and that I would be able to stop them. And I-- I wanted that. I wanted to be the good guy, like you and mom. So I started learning about Erik and how he behaved. And when we knew he would be out of the house... I used polyjuice to speak with his father. And they pulled my memories... and found out for sure that they were involved in illegal drug trade." He shrugged a little, as though it hadn't horrified him at the time. "I didn't know what they were up to, really, but after that I had people come to me sort of secretly, and they pay, just, outrageous amounts. And I never take jobs that seem sketchy. I've got morals, obviously, thanks to you and the family and school. I probably could've just joined the Order, but my clients like to know that I'm separate. That I don't have to go through a bunch of fighting gits - which, by the way, whatever's going on with that lot is apparently mental lately. But anyway, that's the gist of it. It's like... acting, but I get to interfere with the bad guys in a way that, y'know, isn't just me."