I’m laughing too. Your brother is correct. People are not stupid. They know what the Bible says and they know so-called theistic evolutionists are having a delusional moment trying to force-fit an evolutionary paradigm onto Scripture. What they are really telling you is “Make up your mind - either be a Christian in the manner your book declares or don’t be. But don’t try and change your book or your God to fit our science and stop messing with our science trying to say your God “nudged this” or “directed that” to get nature to where it is today.”
Another thing your brother is telling you is “If I become a Christian, it will be in the authentic way. At least I am an authentic atheist. But YOU - you are not an authentic Christian.”
I’m still laughing. I hope your brother reads these responses. He didn’t just win the debate. He literally defined the entire culture war today - AND GOT IT RIGHT.