Do you think it's right that I'm annoyed at my friend and sister for not standing up to a bully?
How come you think they should stand up to the bully?
They should learn to stand up for themselves.
But why aren't you annoyed at the bully for being a bully? Bulling is wrong.
I can't make the bully stop, though.
If you can't make the bully stop, you shouldn't be annoyed at your friend and sister for not making them stop, either. You shouldn't be mad at the victims for being harassed, you should be mad at the bully for harassing them, because that's the real problem.