E, It's not easy sitting on the sidelines and watching them hit bottom, but bottom he must hit in order to rise to the top once again.
Be a good listener that's all you can do for him right now. He needs to figure things out for himself, as you already know. Don't offer up advice until he asks for it.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.