I don’t think you understand what material/immaterial means. Consciousness is immaterial by virtue of the fact it has no physical properties – no mass, no electric charge, no velocity, it can’t be seen, touched etc. That is simply the way things are. Materialism so defined is simply not correct.
I’m sure no one in the history of the Universe has ever claimed the brain has zero effects on consciousness. As usual, materialists attacking ludicrous straw men.