Be calm and cool. You know him better than anyone. He sounds really confused and in need of space... overwhelmed.
Are you willing to ask him what you can do to keep him from going to his brother's? What does he want you to do? Why does he "need" to get away? You know it's easier to DB while he's at home, so it's up to you sweetheart.
Breathe. You've come such a long way baby! He's scared. He needs to let his anger and resentment out.
