Ray Manzarek of the Doors fame used to play the baseline on a Fender Rhodes piano bass and lead with this righthand on the Vox.

Having said that this guy is doing a lot more.

I work with a guy that drums in a band, not content with 4 limbs doing different things he also sings.

As you say I don't see how human beings do it.

If you really want to see a Hammond Organ like the one this guy is playing put through its paces look at Jimmy Smith on you tube, back in the day Jimmy Smith was the Hammond man, the Hammond B3 was his weapon of choice