He doesn't have the power to stop them. But lets say he did. That would affect every aspect of the economy. What I'm saying it's that it's not something that you can just stop on a whim, and proceed with something better as if nothing just happened.
If he does not have the power to stop them, what is the point of having a leader?
Being a leader doesn't make anyone a superman. Shutting down the FED is something Congress wouldn't allow.