How to save Dumb cane that lost all its leaves?

I have a dumb cane that has just slowly withered away to just a stem. I really want to save it because it was sooo pretty when I got it but now it's just. One leaf and a dying leaf. Well really almost just a stem now. What should I do to save Nameless, that's the name my nephew gave him because we couldn't think of a name so Nameless was perfect, lol! I checked the roots and they are nice and white no rot I just don't know what I did wrong to put Nameless in the condition he's in! The reason he's still in the pot he's in is because he was a big beautiful plant and now he's become what you see in the pictures, under the dirt healthy white roots, how do I save him? If he can be saved?

 

I am making a note that this was originally posted as a reply to Dumb cane shedding more growing less, so you have read the comments there.

Even though the roots are ok, I would still suspect too much water in soil that is too dense and does not give room for air to get in. Here is an article with some soil advice:
Repotting a Dumb Cane
If you query soil mix for Dieffenbachia, you will find a lot of advice.

 

Thanks for the info!