Another mom and I were trading childcare for several weeks. Her son and my daughter are both nearly 3.5. He turned out to be extremely violent(hitting, biting, throwing, etc.) towards my daughter and me, and pretty much all the time(they were spending up to 10 hours a day together). I finally ended the childcare swap 2 weeks ago when it was clear that it wasn't working out. During the time they were together, my daughter adopted some of his aggressive behaviors and has been scratching her other friends, and me, as soon as she gets frustrated. She often goes for the face, and almost every time she's with her friends one of them ends up with a bloody scratch on the face. I'm at my wits' end with how to deal with this. Any advice?