Sounds like your son needs to be grounded for a long time...

OP, I wonder what else your son has told your daughter that isn't true?!

at least it was just her arm; it could have been much worse. if I did that to my sister I'd have to fly to Africa to pick my beaten butt up.

Why is this in the intimacy category?

No matter how much you despise your siblings, this is still downright cruel.... I wouldn't do that to anyone, not even justin beiber! ( or maybe I would!)

Well, she's obviously a muggle. Or maybe she just didn't get the memo. It's the swings you try to fly from! Encourage her to try again, better she find out now or she'll be mighty disappointed on her eleventh when no owl comes.

Sounds like your son should donate part of his allowance to pay any costs associated with healing her arm. He might learn not to encourage his sister to do stupid shit like this. Hope your daughter's okay.

This is why having older brothers suck sometimes. My brothers have done all sorts of crap like this.

Lol when I was small I would try to do this to my you get brother, once he had a loose tooth and i told him if he pulled it out now, the tooth fairy would give me more money, so I tied his tooth to a string, then to the door handle, and as I was about to shut it close, my dad walks in. it's normal for siblings to do these things to each other, although as children they are, they don't think of the consequences.

That's what brothers do. Hope your daughter recovers soon.