As for the rape, if you want to be there for her then by all means reach out. Don't be overbearing, don't be pushy, just let her know you're there. It's really all you can do. It isn't "your business" but you can always be helpful, that doesn't necessary mean you're meddling.

I'm going to be honest, I'm not there when Becky is venting, but you shouldn't judge her for it. I have a best friend I vent to about ultra personal stuff because she's the only one I trust to do so. She's the only one I'm comfortable with, who won't judge me and just listen. Talking about it can be really cathartic. It's possible you guys are the only people who've ever allowed her to vent, and because if it she's getting a bit carried away. Not everyone can move on from their abusive pasts alone. A lot of people need professional help. The best and only thing you can do is recommend she see a profesional and support her through that.