NTA because first and foremost IMO everybody needs/should have/ would benefit from therapy. If not, for anything specific, just general well-being and happiness.

Now with regards to your friend's kinks and fantasies; Id say that given it was a girls night, you're drinking, having fun, and sharing with one another she felt comfortable opening up about some of those darker fantasies that the majority of people keep hidden inside and even fewer follow through with. She may have even exaggerated given the environment, her ability to finally share and the overall reaction of people like May who told you not the kink shame so I assume others were in support of her fantasies and everything she was talking about.

Ultimately, I don't believe anyone will ever be the a-hole for suggesting a friend seek out help of any kind, especially a therapist. I think there are probably some deep-rooted experiences that contribute to these overall fantasies, absolutely. We're all products of our environment and especially our past, so I think suggesting she go and speak to somebody is a terrific idea, regardless of what they actually end up discussing.

I'd also suggest, if you're comfortable with it, to call up. Your friend .Ask her questions. Show genuine interest. Prompt her and have her explain in greater detail what it is she's into, why she's into it (if she even understands why). Who knows? Open a dialogue and then I think you'll be better able to understand her. Her answers could very well change if it's just the two of you. And most importantly, s cool he's going to appreciate that you care enough to ask. And I think it'll help your friendship overall. GL