It is not the “how” that makes the model. You need the “why”, which is philosophy, not science.
Kurzweil’s idea could create the proverbial “tabula raza” brain: capable of processing all the thought that a human could process, but has no inherent idea as to its purpose in the universe except for what the programmer puts into it.
Kurzweil has not solved the perennial “mind-brain” duality question. He thinks that the human brain is just a chemical computer, and if he can duplicate the processes sufficiently it will produce the “mind”, but you cannot produce a “mind” without its purpose and place in the universe being determined.
People do not create a sense of purpose on their own; purpose by its nature is something given to the person. Any purpose you can create for yourself can be just as easily dismissed. Anything so easily dismissed was never really important to begin with. It is because purpose is given from without that it has meaning and importance to us. We do not regard things in our life as important because we made a decision (wife, children, bacon, etc.) but because it was put into us and we recognize something wrong when people do not consider these things important.
So it is with machines. Machines througout history have had their purpose given to them by us, their creators. A machine mind would need a starting point for all its projected sense of morality. Be very wary of whoever programs that first machine “mind”.
Beyond the philosophical questions, the human brain seems to have a storage capacity beyond what could simply be measured by a cell-count alone. I think I read somewhere the brain has a trillion cells; I don’t know if that is right, but let’s use that figure as an example. In this digital video age, we know that a single movie can require from megabytes to gigabytes for storage, depending on resolution and compression. How many movies (to say nothing of life events) have you watched that you can replay in your mind? Of course the mind is analog, but how much storage must it require? Is that few pounds of gray matter alone really capable of such storage, or is the mind simply a terminal connected to a larger storage elsewhere?