It is on and off ... constantly! I don't think they can do it consistently because it goes against the fabric of our humanity. I see JWs struggle all the time with shunning family and friends they really don't want to shun, and instead of taking responsibility for their own behavior, they blame the person being shunned. I think they just tell themselves that to salve their conscious about doing something they know is not right (shunning).
I am very sorry for losing your father, but I am glad you got to see him before he passed.