Why is your son bullying? Could it be because he wants kids to be afraid of him so they leave him alone? Or could he be defending himself thinking he is being bullied? Have you asked him why he hates you and wants you out of his life?
I have been all here before in my childhood. I hated my mom for different reasons, I thought she let kids bully me, I thought she wanted my life to be miserable because she kept taking me to my psychiatrist and keeping me out of school, she wanted me on medication, she always got mad at me for my emotions and my obsessions. But yet I didn't hate my dad even though he agreed to take me out of school and he took me to my psychiatrist, he also had me on pills. For some reason I targeted my mom. I thought kids were picking on me when I was 13 so I defend myself not even realizing I was being the bully.