Ali, continue to be a safe place for him. No pressure. Just let him know that you are there for him if he needs anything. I think it is huge that he felt comfortable enough to confide in you about this.
It is great that he went to the doctor and is even taking AD's. I think I read on your other thread he may go to counseling. He knows something is wrong and is trying to do something about it. That says a lot about him.