Long story short, I intern for this company based in west coast. I work remotely and am based in New York. For the past few weeks work has been really hectic. 

About a month ago I woke up to some messages from him on our slack regarding an issue with my work. I immediately corrected it and the day went on. But now he has made it a habit. Since he is a workaholic who stays up late and does his work, he writes every stressful work related comments for me at night which have just peaked my anxiety to the point I cannot sleep. 

Every day my mind stays awake in case he writes some shit and I am not caught off guard in the morning. I have developed sleeplessness because of it. And because my boss is such an ass, all of his messages are just basically him blasting off at me for every minor detail. 

How do I tell him to hold off this until morning where I am more collected and less anxious. I have mentioned it once to him that I am not comfortable with him sending me work messages late at night but he really doesn’t seem to care. He has this whole ‘my way or the highway’ mentality which is driving me mad.