My 11 year old son frequently hits, pushes, his younger siblings, ages 6 and 5, when no adult is around. It is very much intentional in trying to hurt the others. He will provoke his siblings with acting wild and then hurt them somehow. Obviously, talking hasn't helped. I know his older brother (13) sometimes bullies him, so is he bullying his younger siblings? We homeschool so there is plenty of opportunity for this to happen quite often, many times a day. He is a quiet child who prefers to be by himself, so I am not sure how effective isolation would be.
Thank you for your help,