Originally Posted by
twotwothree 
We feel like if we do not confront her enabling behavior the situation will get much worse and we will lose any ability to help we have at the moment.
Can I gently ask why you're considering confronting her about her enabling behavior rather than talking to her about her safety and well-being and that of her child(ren)?
SA is about control. If her AH has assaulted one of their friends, as her friend, I'd be worried about how he might be trying to exert control in his house as well.
I'm a survivor of intimate partner rape and domestic violence, so, perhaps my experience is coloring how I read the information you provided. However, AXH assaulted not only me, but his next GF. His controlling behavior isn't limited to just one person, it's how he deals with relationships.