Anyway. Of my kids we have Alecto who might have had some overlap at Hogwarts, but she still wouldn't like him on principal.
Dung, who is older, and in the Order. Probably knows Frank. Who knows, maybe Frank was part of Dung's poker league at Hogwarts? Either way, Dung probably thinks Frank is a good bloke.
Xeno was also class of 71, but a Ravenclaw. Still, they probably had some classes together. As long as Frank didn't make fun of him, then Xeno likes him just fine.