All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
If a mother gifts her two daughters but they are young and did not yet reach the age of puberty or the age of distinction, then they are not eligible to possess the gift. Therefore, for this gift to be valid, it is their father who is still alive who would possess this gift for them because he is their guardian and it is not valid to possess or accept the gift except by him.
However, if they are young but they reached the age of distinction, then it is acceptable for them to possess a gift for themselves, but there is a difference of opinion among the scholars about the validity of a child above the age of distinction possessing a gift. On the other hand, if they did not possess the gift until their mother died, then the gift goes back to the inheritance.
Therefore, according to the above cases where the gift is not valid, you (the questioner) should give back the gift to the heirs because it is an inheritance.
Furthermore, you should know that your father has the right to take what he needs from the money of his daughters without being unfair to them, and without taking what they need and like. For more benefit, refer to Fatwa 89942.
Therefore, if the father had taken from your money according to the above, then it is permissible for him to do so. However, if he had taken from your money what he did not need or that he had taken unjustly, then it is not permissible for him to do so. In which case, we advise you to take the matter to an Islamic court so that it will give you back your right from him.
Allaah Knows best.