We are all talking and most of the replies dis-encouraged moving forward with this engagement; however the problem owner has already made his mind to go on. Personally; I think this is his heart talking not his mind.But because he has an objecting mind; he started this conversation seeking relief. I can see this in his words describing her as a "victim" of her mother's deeds and he has to "save" her
I think since this is his decision we should try helping him in his next step; I think it is ok to move forward with the engagement; but keep in minding every word said here along the engagement period. Assess her again and again; at the end it might be a life-time decision . One more thing; talk to your family; they are close to you; they understand you; and they would be much helpful for you than everyone else; even her and even us over here; and they may see what we all cannot see.
Sorry for using English