My gut reaction would be that the only reason the kid wants to go is because his friend (& dad) are going - and that it's some sort of peer acceptance/fitting in thing. But it could be that there's more to the story.

I think kids that age are idiots who often decide something is much more important than it really is. 90% of the time, that thing (activity, clothing, album, whatever) that they are insisting is super important is something that they won't even remember - or if they do they'll be laughing about it - 3-5 years later.

Which doesn't mean it isn't important to them. Just means that they have a warped sense of what is important. But it feels like this could be a good opportunity to talk to him about why it's important.

I also think it would be a pretty good opportunity to have a more comprehensive discussion as to why you disapprove. What is it about the lyrics you don't like? How is it sexist and misogynistic and why you are worried about that? How is it sex charged, and why certain perspectives on sex are damaging to future relationships. Why you have concerns about language and violence.

To be honest - in high school and heard (and some days probably said) the f word more than he'd hear it at that concert. And that's likely true for him as well - the word gets thrown around a ton in high school. So while I don't like the language - I'd worry less about that than some of the other concerns. But even if you were to let him decide on his own, I think you could have a conversation about your concerns and why they are concerns rather than just saying "I don't like the sex charged lyrics."

Good luck!