how can we as parents of a 21 yr old drug addict help him without enabling him anymore
Enabling is a hard thing to figure out, It was the hardest thing for me.
I would say to say what you mean and mean what you say.
If you set up consequenses you have to stick with them.
I know when my daughter was going through her addiction, We never gave her money. we made sure she had the food and warm clothes. She couldn't live in my house but we would meet her and take to lunch etc. It was sad but we knew what she would do with money or anything of any value. Its tough watching this self distruction happen before your eyes and it makes you feel helpless but never ever give up hope and never doubt yourself.