You are going to love that nephew to death
I am sorry for your loss. It is heart breaking.
The sad truth is most never recover. At some point the natural consequences of all his decisions and actions are his. He will spend that five and much much more before he changes. There is nothing YOU can do. For your own sanity I highly recommend getting into some family support group such as alanon or naranon for your own sanity.
This is not your battle. You have nothing to offer your nephew in the way of experience, strength, or hope. All you can do is muck up what might be his bottom by helping him out.
Shed your tears. Pray for him. Let him walk his own path of pain.
I did. You have to get enough consequences to want to change, tho.