This is easy to rebut. He is wrong about macroeconomics. But that's because every macroeconomic theory is wrong by design.

It is impossible to come up with a macroeconomic model that perfectly describes reality because economic realities are far too complex to be modelled. That doesn't mean there is zero truth or value to these models, but it means they are certainly wrong, and that is is healthy to approach all macroeconomic analysis with a critical mind.