Older Man ADVICE!!

Ava • Ava PURA VIDA 20% CODE: AVASCHLOTTMAN20

So my friend has recently been “meeting up” (hanging out) with and constantly texting this guy who’s 28 years older than her. She’s 17 and he’s 46. He’s been flirting with her (a little bit) and she’s been flirting back. What should I do as a close friend of hers? I don’t want things to go too far, ya know? No one knows that they talk. He also has a GIRLFRIEND but he claims they’re just friends.