Moreso, the only reason why I feel he might be angry is because the work of the Alfa in your life has been defeated, his primary role is to teach you islamic beliefs, but you've chosen your path which is fine
My dear sister, lets get this clear, a Muslim can answer a non Muslim greetings but not Teslim, tho, there's a way to answer that, your Alfa is not sinning if he chose to not answer you, more also