Test results were all negative.
Blood results were normal.
UTI results were normal.
Vet suggested we take him to a Neurologist. That route is too expensive.
Instead, we are going to try a few cheap alternatives.
The first thing we are going to do is change the litter to "Cat Attract".
The next step is to try a cat calming collar. "Good Behavior Calming Collar for Cats" by Sentry seems like a logical choice since it's only $12 and theoretically lasts for 30 days.
After this, we will try steroids (assuming he has brain issues). However the possible side effects of loose/runny stools doesn't appeal to us.
Wish us luck!