Regarding protecting your daughter,
This is just my personal experience, but I have NEVER had to fight unless I put myself in that situation. I've only been in 1 fight that was not a result of my own actions. I have been in fights over girls, but it was more of a territorial, idiot kids in puberty trying to impress a girl stuff.
I just don't foresee a situation where a guy would have to actually fight because someone is trying to steal his girl. Our society isn't like that anymore. Ive walked around everywhere with my wife, and there have been situations where guys walk by us and completely ignore me and greet my wife and compliment her. Doesn't bother me, they are being respectful, and it makes me feel great that other people see her beauty.
Got a bit off topic there. But the only thing that would bother me is the fact it's been 2 years. Even if the kid was abused by his father.... 2 years, the kid has to have at least some trust with you.