It's just a seven year old.
It would seem to be that the families are feuding over something, that possibly the dead mother had started, however it's totally wrong going after a seven year old at that. For the fact of the matter the little girl is only seven, so she can't understand much anyways but with a disease that eats at her brain I'm sure it makes it even harder to understand, but I could be wrong I've never met any one with Huntington's or know much about it.
The only reason to me it seems that hey are denying the fact that they're using the coffin to intimidate the girl, if that's what they're doing is because it would go against them as a hate crime, which is a very serious thing and can be put to jail for x amount of years let alone parole, taking in to consideration that the victim is a young child I doubt the judge or jury will go easy on them.
Honestly, it seems that they're doing this to get attention and you can see that they're lying in the video it isn't hard to figure out, they're just covering their ###'s.
It's just sick. I doubt that either one of them are sociopaths, my cousin was diagnosed as one and their out ward experience doesn't really fit. They're just butt heads with nothing else better to do.