Older woman talking to my son about her period

I found out that my son befriended someone he saw on tiktok and they've been talking. He's 15 almost 16 and she's in her mid 30s. He liked her content. He said it wasn't anything bad. They're just friends but I went through their messages and her talking about her period with him made me extremely uncomfortable. I know periods are natural and no one should be ashamed of having one. I just don't understand why someone in their 30's wants to talk to a minor in detail about her period. She was saying she woke up bleeding and hers are always so heavy. That she prefers pads because tampons feel weird inside her. Nope. Made him block her because thats weird. It's not even the period talk. If he had a female friend his own age talking to him about it I wouldn't care. I don't like that some strange woman he met on tiktok is talking to him at all. Let alone about her period. Am I wrong?