Hi:
What a difficult situation to be in. The one thing that may help is to try to understand what life lession this is for you. We know that we are all here to learn and people are put in our path to help up achieve this. It may be a lesson in patience, forgiveness, etc. Or to turn this around it may be that you are his/her teacher and the manner in which you handle the situation my help him/her on their path. It may be that they don't discover this for some time though.!
There was a boss in my friends work who was horrible to her staff. She decided to surround this woman with white light every day for the purpose of helping her (the boss) as it was obvious from her behaviour that she was coming from a place of fear herself. The good news is within a few days this woman (boss) changed. Everyone noticed the difference commenting on how nice she had become.
When we try to remove our own emotions to assist I believe the universe will be behind us all the way and work for everyone's highest good.
Blessings
copper