How do you know if a dog is hallucinating?

I knew some guys who bought a pit bull puppy to be their guard dog when he grew up, and to warn them if cops were coming to bust them, but at about two months, he hate a sheet of blotter, and ceased moving. He didn't die. He just didn't move anymore. If they put food in front of him, he'd eat it, same with water, and they took him outside so he could pee and poop, but he didn't move. When the inevitable drug bust did come, not only was he totally useless in warning them, but the cops had to physically lift him up off the couch to search it.