All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
The preponderant view that we adopt is that the financial responsibility for the two daughters falls on the mother if there are no relatives who would inherit from them. However, if there are relatives who are eligible to inherit, such as uncles, then the financial responsibility is distributed between the mother and uncles based on their share of inheritance from the two daughters. In this case, the mother is responsible for one-third of the expenses, while the uncles are responsible for two-thirds.
Ibn Qudaamah said in Al-Mughni: “The summary is that if a child does not have a father, the financial responsibility falls on his inheritors. If there are two inheritors, the financial responsibility is on both of them according to their share of inheritance from him. If there are three or more, the financial responsibility is divided among them according to their inheritance from him. If the child has a mother and a grandfather, then one-third of the responsibility is on the mother, and the remaining is on the grandfather because they both inherit from him in this way.”
Allah knows best.