So let me get this straight...

Her first husband turned out to be the black doctor guy but her family didn't know it because they didn't remember him? It makes sense since the older two brothers seem like they're mixed race, but wouldn't they remember their own father? So he comes to take her away so he can euthanize her back at their church, presumably after getting remarried so he can claim the inheritance? If so, why would he kill his two mixed sons instead of sharing the inheritance with them? They were the ones who were going to get screwed by the other brothers. I also don't know how the girlfriend character was able to be one of the masked people without the boyfriend finding out, especially since she rode with him to the town. Was the girlfriend cheating on him with his dad, the doctor guy?