<human>: I know I'm probably a little young to be entering this sub-Reddit but you guys all seem to have great advice so here goes. 

My friend and I are 16, ever since she was 14 she meets guys on the internet and forms "relationships" with them. Now, I'm no expert in dating but the fact that the (ex) boyfriend of hers was 21 and she was 14 at the time freaked me out. Especially since he lived in Germany and they met on Chat Roulette. They professed "love" yadda yadda, yet never met. My curiosity got the better of me and I googled him. His twitter account shocked me; he had a wife. I'm pretty sure my friend had sent pictures of herself to him (no, not appropriate ones either). Eventually he just stopped talking to her and she healed her broken heart.

I never told her what I discovered. (This sounds quite dramatic so far). Now, she is talking to one of her fathers younger friends. He is 31. They have also never met. All she knows is that her father knew him for a couple of years. I'm seriously worried about her. I know love has no bounds and whatever, but this man is basically twice her age and she is seriously underage for him. (We're Australian if that helps). I find it disturbing this man is "in love" with a 16 year old girl he has never met face to face. 

Does anyone have any advice? Do I just let her make her own mistakes? I don't want her to meet up with him eventually or get upset and hurt again....

Can you give me a shortened version of the text?
<bot>: friend keeps dating older men. currently talking to 31 year old. She is 16. Advice to help her before something MAY happen??