Is it permissible to combine the private funds of the two orphans with the mother's money for the household and daughters' expenses?

The two orphaned girls own the donated money, and the mother acts as their guardian as long as no other guardian exists for them. If they are mature, the mother hands the money over to them. If they are not, she spends on them from it. It is permissible for the mother to combine the money with her own and spend from it on the two girls and herself if that is more convenient and beneficial for them. Scholars have differed regarding the permissibility of the mother taking from her daughters' money for her own needs, and the more preponderant opinion is that it is permissible.