There will be many failures as they attempt to “perfect” their procedure. Unfortunate humans will die. Countless dogs will be put through extreme suffering.
Assume it’s possible, and actually gets done. The unfortunate human will regain consciousness to extreme intense pain, and an overwhelming feeling of complete disorientation.
The sutures will cause pain. The nerve junctions will cause pain. The brain will be faced with an entirely new set of sensations received from the new organs. The person will be unable to handle this. The experimenters will have their torture victim very very heavily sedated and on strong painkillers. They will allow their victim to regain consciousness, and make a video of him saying a few words. The ghouls will then declare their experiment to be an overwhelming success.