Writing a popular scientific book is a great way to present far-fetched ideas without having to face scrutiny. And it's easy to come up with far-fetched ideas outside of your own field, where you don't have the knowledge necessary to find fault with them. Roger Penrose is not an expert on neurology, or on molecular biology, or biochemistry, or quantum chemistry, or even quantum mechanics. He's an expert on mathematics, topology, GR and such. And there's no evidence whatsoever for what he says, and lots of evidence to believe the opposite. As is well-known, Max Tegmark bothered to do the math and confirm what we already knew, which is that the decoherence times are far too short in such a system. Which is pretty much what all of chemistry would already tell you.
Few, if anyone at all, actually in these fields take his ideas seriously. Also, they're not even based on established QM, but his own ideas of gravitational decoherence.