This could easily be left over activity he learned as a child trying to hide the abuse and resulting fallout from his folks.
I don't know about him, but I had to live a continual lie in order to hide the abuse and my acting out as a teen from my parents. I learned it well. So well in fact that when I grew up and got married I was still living the lie even though at that point there was nothing to keep covered up. I would go out of my way to tell an untruth to my wife when it would have been easier to tell the truth, but the habit was so ingrained in my psyche I knew no other way.
While this may not be his problem, it's worth considering at least.
Lots of love,
"Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting 'Holy Shit! What a ride!'" ~Hunter S. Thompson