You need quantum physics to understand how chemistry works.
So, given that chemistry plays a huge role in how the human (or any) brain works, it would be quite a stretch to argue that the brain works with classical physics.
We are often sloppy and sort all the chemistry in with classical physics, but that's a very human-centric approach. In reality, the Universe doesn't have different "domains" with separate rules for chemistry and physics; it evolves according to the Schrödinger equation, and we use Chemistry as an abstraction to not have to deal with nasty mathematics to predict how certain reactions will work.
I think the parent was really referring to "mind" instead of "brain". It's not the hardware of the brain that's classical, but our sense perception and model of the world.
So, given that chemistry plays a huge role in how the human (or any) brain works, it would be quite a stretch to argue that the brain works with classical physics.
We are often sloppy and sort all the chemistry in with classical physics, but that's a very human-centric approach. In reality, the Universe doesn't have different "domains" with separate rules for chemistry and physics; it evolves according to the Schrödinger equation, and we use Chemistry as an abstraction to not have to deal with nasty mathematics to predict how certain reactions will work.