Treating one's children equally

Q: If a mother says to her daughter, "when you were sick I was not so worried about you. But when your brother was sick I was worried to death. See he is a male child and I feared, without him what would be my life then."

Should a mother say all these words to her daughter? Are daughters so useless, although Islam has reached and all of muslims know what our Sahab (peace be upon him) said about daughters. Please tell me what Allah says about that mothers, saying all these words. Does a mother have a right to say anything to children (female), even hurting them?