Daddy is not based on a real person.
Nor is he a bad person.
Daddy is simply a mash-up of all of the bad and absent fathers on the planet. Therefore he is the person that the most humorously bad things happen to. Boo loves her daddy, but does not get much attention from him.
He is written so that children, especially those in split families or those with poor fathers will get a laugh and want to have a dragon to teach their father a lesson.
He is nobody and everybody, he is the man that is so eager to hurt his ex-wife through their child, that he does not realise he is missing out on a loving relationship with his daughter.
One hope is that fathers who read these stories will see that their behavior is ridiculous and maybe stop to think a little from time to time.