After reading his autobiography, he's got a whole lot of resentment built up against that man, and also the stepfather who mistreated his mother for years. So it surprises me that he didn't work at his marriage for his own children's sake.
Probably if the father had tried years ago to at least keep in touch with Lance, things might have gone a different direction, but the man was a complete unknown factor in Lance's life. Sad all around.