Neural lace isn't just some hypothetical concept Musk is cooking up -- there are real moves being made right now to develop this technology. Just last year, a group of nanotech chemists and engineers published a paper about an ultra-fine mesh that can merge with the brain, providing a flexible circuit that could interface with neurons. And it's not only theoretical, it works. They've implanted them into the brains of living mice (the mesh is thin enough to roll up and inject with a needle), and the mice appear to thrive unaffected afterwards.
This is maybe good news for Musk's jam-packed schedule, since he declared he would only take on the neural lace project if nobody else steps up to the plate. Of course, the scientists who wrote the paper are far from making this sort of thing safe to implant in living humans, and they likely haven't even considered the part about seamlessly integrating the AI "layer" once it's there -- arguably the most critical element. In all likelihood, Musk is going to be the guy to tackle it. But who even knows if he'd be able to figure it all out? Let's get to Mars first, then we'll talk.