When I first saw this video, my immediate thought was: you are totally terrified of this horse and he is the boss. You can see it, you approach, he lays his ears back and charges and you go away. CHinga is the boss, not you.
My second question is: if you can't approach him without him attacking you or charging you, who caught and tied him up to the trailer?
My third thought is: if someone came around when I was inside the barn and was chasing my horse around, they would have been caught and held until the cops showed up. If your dad is that big, he should have chased them down and tackled them for animal abuse. Then if it happend like you said, he got tied up and attacked with whips, and there was a chance it have happened a second night, I would have been sitting all night waiting for another attack and they would have been really surprised to find me waiting.
I think you need someone to help you with a horse that is way over your head in experience.