It sounds to me like he is a really obsessive guy. A creep as you called him. We have a couple of guys like that at our school. First off, do you think he is actually dangerous in any way? This sounds like how a lot of abuse starts. First he wants to know where she is at all times, then he wants to know who she was with, etc. If she is with any other guy at all, regardless of how she feels about the guy, he probably gets jealous, right? If he is dangerous, he could start yelling at her, putting her down, all kinds of things. If you think he is potentially abusive (verbal, physical, etc.) then you need to keep an eye out for your friend for any signs of abuse.

If he is just a bit obsessive and harmless, let the relationship run it's inevitable course. He'll find someone else soon enough.

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