I don’t think he claims you won’t be a quadriplegic.
There was a video on either Fox or One American News that purportedly showed a mouse that he had transplanted a head on that was kinda walking/crawling. I wouldn’t want to go through that to end up a quadriplegic. But then again Stephen Hawking should have been dead years ago from ALS but chose to be artificially kept alive so I guess it would depend on how much you wanted to remain here.