Hello,
In Bipolar illness, antidepressant can switch to high phase which is known as manic phase. He needs a mood stabilizer which will help in neither switching him to low nor high phase. These phases comes in episode and they may worsen with time so its advisable not to stop medication till advised. Medication in form of injections are currently prescribed to control his aggression.
Next Steps
Consult your psychiatrist to know more about bipolar illness and its treatment. You can consult me for any help required.