Hello,, My Boyfriend He Used Drugs More Than 5years. And

Hello,, My boyfriend he used drugs more than 5years. And he just leave 1-2months ago. But 3months ago before he leave we had problem because he never trust me or anyone. He blame me do many things bad to him any reason he make up by his imagination. And in 30mins he can changed his mood from nice to be angry. And many times when he got angry he will hit me. Sometime he knew he was sick should see mental doctor. But sometime he not accept he's sick. Me and his friends trying to help him. But we really doesn't know what should we do for treat him. Manythings he talk are look like he's in dreaming. Could you please let me know what should we do, thank you.