I obviously have no idea the extent of what happened to Coach McCarney. From personal experience I have went through something, that from the register article, sounds quite similar. Had medical symptoms that caused me to go to the ER. As the evening went on they got progressively worse. Could not swallow, loss of some function on one side of body, etc. The initial diagnosis was that I had had a stroke (was 28 years old at the time)
Had a battery of tests done, including MRI, and spinal tap. All test results came back negative for a stroke, though all of my symptoms said otherwise.
Eventually everything bounced back to normal. The neurologist diagnosed it as "SPD- Some Damn Virus". He said that a combination of stress and just working too much, just caused by body to hit the reset button.
This was just over 6 years ago and have had no problems. Let's hope that it is possibly something similar since the article states an "undetermined illness" and not a stroke.
Thoughts and prayers for Coach Mac and his family.