I watched a "locked in" man use a computer mouse with a brain implant in 2002. It remains to be seen if this is actually better than what's been done before other than torturing a bunch of monkeys running needless experiments.

Also I doubt Musk had much to do with the brain implant other than being someone to push people forward and being a bag of money for it. Did he design the implant? Did he insert it? Did he code it?