What about the brain is not modelable? It clearly exists in the physical universe and we clearly have the capacity to simulate physical things to different degrees of approximation. You might not be able to simulate a mind on a thumb drive but you can drill down all the way to simulating every quantum state vector in the volume of a human mind and nervous system if needed and just slow down the internal computational clock. Maybe you need a computer the size of a warehouse and a digital second of thought might be the equivalent of a year to us, but it doesn't seem impossible to simulate the physical system of the brain from first principles.

Getting a model of a brain from a living or dead human seems like it might be impossible. No idea how you could scan or image someone's total brain.