Frazzemrat1
Free Ranging
One way or another, I would find that Rooster a new home in somebody's freezer. If you can't do it yourself, then I'd advertise him as a problem rooster, come get him and he's yours.
I don't tolerate any animal that attacks people, and especially children. It sounds to me like this lady you got him from may have been trying to get rid of a problem, and you ended up with it. Put him down, or get somebody who can do it for you.
ETA: I'm adding that I know some people can calm and retrain problem roosters, but your kids are really too young to be able to establish themselves with this rooster. He'll remember that they are afraid of him and in his mind, they'll be less dominant than him until they did establish themselves as more dominant. Since they can't, he's gotta go.
I don't tolerate any animal that attacks people, and especially children. It sounds to me like this lady you got him from may have been trying to get rid of a problem, and you ended up with it. Put him down, or get somebody who can do it for you.
ETA: I'm adding that I know some people can calm and retrain problem roosters, but your kids are really too young to be able to establish themselves with this rooster. He'll remember that they are afraid of him and in his mind, they'll be less dominant than him until they did establish themselves as more dominant. Since they can't, he's gotta go.