Not knowing all the pertinent details of this case it's almost impossible to answer you. And since you are a co-defendant you asking the Judge for a reduction in his sentence means that you will have to point the finger at someone else. His appeal would involve finding judicial error in his trial. The sentencing phase is something entirely different. He can appeal his sentence, sure, but the Judge doesn't have to reduce anything if he so rules.
You said "certain chemicals" sounds like everyone was cooking meth to me.