You don't know that her background was "abusive." But even if it was, the answer is not to "build her up." The answer is for her to build HERSELF up. No other person -- mother, father, week-old boyfriend -- is going to do it for her.
I don't think this kid deserved to get shot. But I don't have much sympathy for her either.
Emotionally healthy parents do not try to collect their estranged but loved daughter from a bad situation by shooting at her and her boyfriend.
This girl grew up in a dysfunctional family.