Natural Freedom

I know that I should be supportive of my friends in all the stuff that they do and I'm usually pretty understanding of the things they do but this is just something I can't find myself standing behind. So here's the story of this girl.

My friend is 20 and the girl he is now engaged to is 19. This girl already has a kid thats about 4 years old and she had this kid with a 50 year old man. She then dated a 60 year old guy after that. Her reason for doing so was because "they were fun to party with." She took my friend's virginity and now he's "in love" with her.

Now, my friend proposed to her about 2 weeks ago and they had only been dating for about 2 months then. About a week ago, he calls me and says he needs to talk. He rushes over to my house and he was a mess. This girl freaked out on him because she found out he lied to him. He told her he didn't watch porn and she found out he did. What ensues from this tiny little revelation is just completely over the top and kind of funny to anybody looking at it from the outside.

It started by her pushing him out the door, throwing his Xbox 360, his laptop, his clothes and pretty much anything else worth anything inside the apartment out the door and into the muddy yard. She then took every single Xbox game he had and snapped them in half. She took his keys and hid them from him and told him he couldn't have them back until he came with her to drop her brother off at her parents house. Before they left, her brother threw a full pop can at his brand new truck he got in December, leaving a dent in it. Then she tells him she's pregnant and she's getting an abortion if it's for real(which tore him up).

After she drops her brother off, she finally gave his truck keys back to him but as they're driving back to the apartment, she locks the doors and asks him if he wants to die tonight. He obviously said no and she responds with "Well, we're going to. I'm driving us into the pond behind Wal-Mart tonight." He said he wanted to get out of the car but every time there was a red light, she blew through it and kept going. She didn't do it obviously since I can tell this story now but to add to all this, when him and I were talking she was texting him asking him stuff like "Can you at least stay with me for a while until I find a new man, I hate staying here by myself." This obviously isn't love!

I told him that he shouldn't go back to her, he needs to get his ring back, leave her and don't look back. I also told him though if he absolutely feels that he needs to be with her still, to slow it down with her and tell her he doesn't want to get married as soon as he had planned to(July 4th) and call off the engagement for now and save his money for a better wedding experience and all. Well this didn't happen, the next day he gets back with her and this time decides that he's going to get married this THURSDAY! I want to tell him that he's making a huge mistake and after all that happened, this can only end badly but I don't know what to say to him. Help me out here Reddit!