He was legitimately crazy. He was also a genius. There's a super fine line between crazy and genius and 'ol Scary Terry jump roped with it.
Given his extreme paranoia, I wonder what his opsec was like. I'd imagine it was either something extreme and unpractical to the point of significantly impairing usability or it was a bizarre collection of contradictions. I'd guess the latter.
Best programmer to ever have lived, RIP.