So this girl comes to me for emotional support

[splashpot]

So I used to have this crush on a girl who lives in my dorm. This was about 2 years ago. I took my shot at her, but she ended up choosing some other guy. Eh...I got over it. I've been out of the country for the majority of this past year, so I haven't talked to her much at all until September when school started. Ever since school started, we've hung out a lot and we've become pretty close friends. However, I no longer have the slightest romantic interest in her anymore.

She was in a pretty seriuos relationship with that guy until a few weeks ago. Apparently it ended badly and she is an emotional wreck. From what I know about their situation (I don't know all the details and it isn't my place to ask about them), the guy was being kind of an [censored], she put up with it as long as she could, they finally broke up. I never liked the guy. I always thought he ignored her too much. Now that they're broken up, I get the feeling he's doing everything in his power to make her feel guilty and jealous.

Now my friend spends a lot of time in my room. She doesn't want me to know, but I can tell she cries a lot. She still wants to get back with the guy. She tries to talk to me about it, but I obviously don't think it's a good idea for her to keep trying with him. Not because I want her for myself (I don't), but because I don't think he treats her right. I can tell that she's putting 10 times more effort into the relationship than he is.

She called me today. I could tell that she was crying. She said she can't calm down. She said she's still working at their relationship because she wants to make sure she "doesn't have any regrets". I don't exactly know what that means, but it just looks like her serious inability to let go.

So what do I do? I want to help her out because she's my friend. She's still very much in love with him. Should I convince her to let go? How do I do it?