Decorator pattern for an application
The whole idea behind decorators, proxies and drapers is that they encase a single object. Yours seems to be serving two masters and has far too much knowledge of the different objects in your system.

It hard to get a picture of your models from the question - but it seems like you are missing a key relationship since you are passing binder and 
credential around together.

Also instead of creating your own proxying methods you can simply extend the Delegator class but first you have to figure what you are actually proxying and stick to that object.