My best friend has a crush that I'm not sure is good for her.

mu

So, I made a previous post about my friend who likes a guy that is 29 and she's 19. She doesn't have daddy issues, because she said he's the only guy in that age group she likes. They met several years ago while she worked at a summer job. I'm just worried he's just going to hurt her. She said she doesn't want anything serious, but she's a virgin, so I think casual sex is going to be hard for her. By my bad advice ( play hard to get) I have made sure they haven't talked too much and she doesn't have his number. He really likes her and all of his friends at work won't talk to her out of respect to him. I actually met him and he seemed very nice. He's extremely charismatic, relatively good looking, and makes a lot of money. I would say, ok, go for it,... but...there's a few things that struck me odd. I caught him sneaking pictures of her walking to and from her vehicle two different times. He caught me catch him once and we laughed. I guess maybe it's romantic, I don't know. She's told me he likes to watch her while she's working, but she's flattered by it. She's very beautiful and some of the other guys will try to watch her and if he catches them, he finds a way to stop it. So it sounds like he's a little jealous and/or protective. I don't know if I'm preventing something that's great and romantic or if I should keep her from getting involved with this guy. Any advice is greatly appreciated!!