I know, it's hard to move forward when the past still haunts you, and I know that for me, I had to deal with both before I could move anywhere.
Learning from the past gives us lessons to take to the future so that we don't repeat the same mistakes. Sometimes we do anyway, but we are a little wiser next time around and it isn't as mind-jolting as it was in the beginning.
Same for him, hopefully he will pick up tools at rehab that will help him fight addiction when he leaves and learn a better way to live. If not, next time he knows the drill.
Just live in the day and let life unfold as it may. They say that when we live in regret of the past and fear of the future, we lose all the beauty in today. Enjoy the day, it's much too beautiful to waste.
Hugs