Does billie joe Armstrong know about fanfic or slashfics?

Answer 1

Yes. He's read a few. Here's a quote from him about it, "Tre reads the dirty ones. I've read a few. It's flattering and sort of weird at the same time. I don't really know what to think about young girls thinking about old men like that. But the ones I have read were very well-written and as long as kids these days are still being creative and writing, then I think it's cool." -Billie Joe Armstrong.

Answer 2

It's possible that Billie Joe Armstrong is aware of fanfiction and slash fiction, as these are common elements of fandom culture. However, his personal knowledge or thoughts on the subject have not been explicitly stated.