Not your typical request....

I have two acquaintances. They are friends with my friends and we all end up hanging out together as a large group. Everyone who knows them agrees they are awful for each other.

The girl came from an emotionally and physically abusive family. She's a condescending patronizing "mother knows best" type (even though she's in her early 20s and about 8-10 years younger than most of the people in our group she is being patronizing to). She knows exactly how to push someone's buttons and does so for the sake of being "right." She really doesn't like being wrong or having her view/way challenged.

The guy in this relationship is an alcoholic who has some sexist beliefs about women. I don't know much else about him to offer perspective into his personality.

The two together fight explosively and violently; verbally in front of everyone and physically on their own. They are the type where the one driving will pull over, regardless of where they are, and throw the other out of the car, and then drive off if the fight is bad enough. The girl, being patronizing and unable to compromise, intentionally pushes his buttons and he being an alcoholic with sexist tenancies responds exactly how you would expect. He has hit her. She has called the police on him.

They've broken up a dozen times. They get back together every single time (repeating about 3 years now). Everyone who knows them knows they are absolutely 100% not right for each other (hell they aren't really right for anyone at their current maturity). At this point most of us suspect they only get back together because both of them are too afraid to be alone.

Any advice on how to make them see how absolutely wrong they are for each other?