Which person developed new economic ideas based on governments borrowing and spending more money during an economic crisis?

The appropriate response is John Maynard Keynes.

He was a British business analyst whose thoughts in a general sense changed the hypothesis and routine of macroeconomics and the financial approaches of governments. He based on and incredibly refined before work on the reasons for business cycles, and is broadly thought to be a standout amongst the most compelling financial analysts of the twentieth century and the organizer of current macroeconomics.