my 17 yo guy friend likes a 29 yo

My guy best friend is 17 (soon to be 18), and he likes a 29 y/o woman. Their friendship started a year ago when he was seeking work related advice from her.. I get that it's his preference, and it's okay...I even tease him about it sometimes.

But yesterday, I found out that she flirts with him SPECIFICALLY when she's ovulating 😭. Like, you're 29! Why would you do that?! So, I told him it's not right and that it’s giving major pedo vibes.

And bro, today my friend told me she sent him a message saying, "But I'd need vitamin U for that."
That’s so creepy. He likes her, but she's mature enough to know better than to flirt with a minor as an adult.

klhdjxkankj 😭😭 Any opinions or advice?

[Btw, Idk what flair to use, so..I just chose this]

edit - after I posted this, we kept talking about the woman, and he admitted that she does give off weird vibes sometimes. Then he asked me what he should do, and I told him to back off because 😭 my bacha is getting groomed. But he can’t really cut ties completely since she’s related to his work so I told him not to flirt back.. try not to think about her.. and keep the conversation strictly work related.

edit 2 - Just found out she’s been flirting with him since he was 16. And when I said he’s been getting groomed, my bro didn’t even understand what that meant. 😭
He thanked me for 'enlightening' him. He’s going to block her.