I think there is always hope but as mentioned above hope and expectations are very different things. What you and I would think is rock bottom may just be a minor hurdle or a temporary inconvenience on the path of his addiction. I think keeping your expectations low at this point is wise. In time, more will be revealed.
Take advantage of this break of worry for you. He is where he needs to be, safe and being looked after by professionals. Now is the time for you to do the same, take care of you.