YB starts off with ~'we all agree mind is a product of the brain'. No, we do not all agree. Did we ever find the 'bottom' of matter? Has are search to find 'irreducible particle' succeeded? Is it not the case that as we threw more energy into our apparatus we found more elementary matter? Did we in fact finally arrive at a coherent unified model that fully explains material reality without "mathematical woo"?
So the honest position is that we have patchwork understanding of reality at various scales, and the reductionist program of Democritus et al has not been conclusively shown to be the ultimate truth. It seems that mind is bounded by the body but that 'boundary condition' depends on various reductionist assumptions about materiality.