I don't think there's even really a word for someone who's your dad's cousin... Is there?
I believe that is called a "first cousin, once removed."
As for #s of cousins, some families generally use the term "cousins" for more than just first cousin. More complex relations, like the aforementioned, 2nd cousins, various step-relations, etc., get lumped into the easy word "cousin." So maybe if your parents had 60-80 cousins each, that would explain why. That or their families REALLY liked procreating.