If I were the father, I would have picked my daughter up from school and followed the bus home. I’d let her point out the kids giving her grief as they got off the bus. I’d note which houses they entered.
I’d visit the house again that night, alone, around 8 pm. I’d knock on the door and politely explain the situation to the father, and tell him that if he didn’t put a stop to it, I’d take it out on him, one way or another.
This would be a private conversation.
I’d do the same. I’d also hope the Father wasn’t one of those “my home is my castle, .45 with a round in the chamber next to the door to deal with threats” types, and the story of my death wasn’t met with cheers from the “some people need killin’, especially if they came to
my house and threatened me” types on a message board.
If some guy came to my house at night and threatened me in the manner you just described, he'd be looking down the business end of my ever-present pistol while I had my wife or one of the kids call the police. While we waited for the police to come arrest him, if he so much as twitched in a threatening manner, I'd end his miserable life right there on the porch, and it would be 100% legal in the great state of Texas.
I strongly suggest you rethink the idiocy of entering someone's property to make threats. That kind of thinking (or lack thereof) might get you killed. For your own sake, I hope you're just swinging your epeen and don't seriously act out like a $2 thug. Plenty of good people believe wholeheartedly in the castle law.