Okay... see my thing here is how good is this friendship? Is it that kind of 10 year friendship that will probably outlive both your marriages? Or is she just your roommate?

If it's the latter of the two... well stay out of it. It simply isn't your business and it's also likely that as someone who doesn't know either of them as well as they know each other you're misinterpreting things. How does an "abusive long distance relationship" work? It's like cyber bullying- there's nothing stopping her from saying okay and wearing whatever she wants, going out with whoever she wants, and telling him whatever he wants to hear. It sounds like she's the one using her agency to do whatever this guy tells her to do, which while it may not be your cup of tea is her choice. Stay out of it, respect it, and don't wind up on some potential psycho's kill list just for a girl you share a room with.

Now if she's a really really good friend... don't ask her or say anything. Take her phone, laptop, whatever she contacts him with and delete his info and block him. Let a few days go by and introduce her to some new guys. She'll take the message when she sees you really mean it and she trusts you to know. At 19, the quickest way to get over a guy is to get under a new one so... go ahead and get her mingling with some of better quality because chances are if you're a good enough friend, you know her type and you can find a guy who is everything this current one is but better.

There's no such thing as a long distance marriage proposal... where is the ring? On an e-vite? In the mail on the way? Yeah no. Texting someone "Will you marry me?" is not a real proposal. That's like getting a plastic ring from a coin machine on your wedding day. That proposal... In all likelyhood its some cheap trick to string her along. You can quote that to her and say I said it xD Because it's damn true, only a 19 year old would believe some stuff like that.