It is obligatory on the father to support the children by providing them with food and drink, clothes, medicine, housing and all that they need for their living.
Apparently, Fatima Al-Zahra (peace be upon her) is the only daughter of the prophet (peace be upon him and his holy progeny). Others like Zainab and Rouqayyah are daughters of Khadijah. Some even say that they were Khadija’s step-daughters.