I want to direct everyone’s attentions to these Friedman papers.1 They demonstrate how Keynesian Friedman was.
What differentiated Friedman from Keynes was a matter of empirics. Friedman observed that the nominal income path of the economy was a function of monetary policy, that it was money supply, not liquidity preference, that caused recessions, and that the quantity theory was true. Friedman also trusted bureaucrats less after years of failure. All these conclusions, however, were within a Keynesian framework.
Friedman, Milton. "Comments on the Critics." Journal of Political Economy 80, no. 5 (1972): 906-50. Accessed June 2, 2021. http://www.jstor.org/stable/1830418.
Friedman, Milton. "A Monetary Theory of Nominal Income." Journal of Political Economy 79, no. 2 (1971): 323-37. Accessed June 2, 2021. http://www.jstor.org/stable/1832113.