"About a year ago, the employee said, Ferrill started saying he believed Miller workers were coming into his home, bugging his computer and moving chairs around."

StoneCutter you beat me to the punch. This is the talk of a paranoid schizophrenic. Which means, as crazy as you can get. Psychotic.
His co workers who heard this talk, needed to try to get him some mental health counseling. Might have helped him a lot, might not have helped him at all. But they should have tried.
I know that in Georgia you can get a person committed for an "involuntary 72 hour" committal, the docs will check him out, if they determine he is really nuts he may be kept for quite a while.