He's using V4, not R2. Remesh will preform a similar function, though I'm not sure how easy it would be with all the appendages. You might also want to try splitting up the mesh to allow for more polygons in the area you're working on. If the head was split from the body for example (which would be easy to hide if he was…
Depending on your machine, you'll have a maximum number of polygons/vertices available per subtool. As for the blockiness, it's going to boil down to the topology (wireframe) of the base mesh on the lowest subdivision level; 6 million points might not be enough to sufficiently produce the detail if the majority of those…