Not to speak out of line or anything but, I had a serious head injury two years ago. To the point, where my doctors said it was a miracle I was even alive.
In the aftermath of such an injury or however you wish to describe it, you do become slower. You tend to see the words in your head but, it takes that extra bit of time to get them out. Your emotions also go up and down, from one extreme to the other. You may also have some issues with different senses
It can last for awhile but, over time it does get a lot better.
The bottom line is, he's still here and the full time whistle ain't blowing anytime soon