I think that being unable to relate to Kevin's dad, was an intentional part of the show. Because Kevin himself didn't ever relate to his father all that well. It was a bit of a commentary on the status of the nuclear family during the time period when the show was set. Dad was aloof and gone and working most of the time, Mom was at home taking care of the kids and the family home.
There were a couple of episodes when Kevin actually did have some moments with his dad, or FELT he had, and it made it all the more poignant.
That's my take anyway. I loved that show.