Do you always have to have your parents back??

Real talk, not every parent do right by their children. But often if the child turns around and not do right by their parent(s) (becuase of their parents' actions towards them), why do people say "well, that's your mom/dad". Example, a friend of mine dad's rarely talks to her. He doesn't call her for birthdays, holidays etc, however when he does call, it's pretty much to "borrow" some money and he will tell her "well I am your father". Should she be entitled to lend him money just because he's her father, though he doesn't care to be fully in her life?