During a talk with NCIS Director Leon Vance, Admiral McGee also expressed some disapproval towards his son's job, believing that being an NCIS Special Agent was actually a paper-pushing job despite Vance attempting to convince him otherwise. It was later revealed that he had been diagnosed with cancer.
In Season 4, "Iceman", Tony asked McGee if he always told his father what he was up to, McGee answered "Every day." However, later episodes showed that McGee and his father were never close, so it may be possible that McGee was lying.
Another example of this was seen in the season 6 episode "Hide and Seek" When Tony asked McGee about hiking, Mcgee answered that his father used to take him hiking all the time as a kid. But in "Squall", McGee said that his father's only family was the Navy, and was never around.