[roland35]

I am sorry you have to deal with this co-worker. No one deserves to be treated this way. I agree with other responses here that there isn't anything you can do to change his behaviors since the boss doesn't care. The only thing you can do is leave.

I disagree with any advice on engaging with him at all. As a victim of emotional abuse myself, I think the best way forward is to completely ignore him as best you can - there is nothing you can ever gain from trying to talk to him (except for the bare minimum required for work). It is so tempting to tell him what you really think but trust me - he is better at being a jerk than you are (he has a lifetime of practice) and it will probably backfire.

Try to get a new job and maybe when another 5 people quit the boss will realize that there is a real problem with your coworker.