I'll play devils advocate and say well she did just pop up on your page, she knows a lot of people you know and she's very young.
it sounds like you went through a tough time with him and who knows you might save her some heart ache or at least you can put it out there so that she knows the truth and then leave it up to her to make up her own mind. I know I was in an abusive relationship and I wouldnt wish that upon anyone else either.
You've put it out there so now you can let it go.