Information is information. Everything can be described in binary terms.

Binary digit is how actual brain scientists understand bit, because that's what it means.

But "brains aren't binary" is also flawed. At any given point, a neuron is either firing or not firing. That's based on a buildup of potentials based on the input of other neurons, but it ultimately either fires or it doesn't, and that "fire/don't fire" dichotomy is critical to a bunch of processes. Information may be encoded other ways, eg fire rate, but if you dive down to the core levels, the threshold of whether a neuron hits the action potential is what defines the activity of the brain.