It's simply saying that "consciousness" is related to the brain, but doesn't explain the subjective feeling of consciousness.
The stuff about the single cell organism's supposed consciousness is just a lame analogy.
This is what you can do if you are a "philosopher" - just sniff some glue and write stuff down.
That human consciousness is a function of the boundary between the brain and the environment across which senses pass; the internal processes virtualising the external environment. The human consciousness then also has awareness of itself, sensed across the boundary, and re-virtualised within; akin to Hofstadter's loop.
At the same time, Grosz breaks down the concept of consciousness in the other direction, looking at this idea of virtualization within a sensing boundary in a single cell organism. The mechanism of such consciousness can be understood in this case as a mere transfer of information. From there its turtles all the way down.
Such a view is well within the standard model.