Think FTD.

John Mackey wanted to be the best professional football player he could possibly be. He was a thinker, a doer and he wanted to accomplish things in the best possible way. His trademark was his big cowboy hat that he wore all the time. He started wearing a baseball cap on top of the cowboy hat, and things just started to escalate. Since I knew something was wrong, it was that I'm just going to keep on until I find the right diagnosis, and I knew it was right when I heard it even though I didn't know what FTD was.
Keep in mind, you're living the disease, not the person that you loved before they showed symptoms of the disease.
Think it's Alzheimer's? Think again.
Think FTD.