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, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
If the heirs are only those mentioned in the question, and the deceased did not leave any other heir, then half is for the daughter as her legal share, as Allaah says (what means): {And if there is only one [daughter], for her is half.} [Quran 4:11]
The other half is for the son's son by Ta‘seeb (by virtue of having a paternal relation with the deceased and not having an allotted share, so he gets what is left after the allotted shares have been distributed); and the full-sister is not entitled to any of the inheritance because she is excluded by the existence of the grandson.
It should be noted that the division of inheritance is a serious and complex matter. It does not suffice to settle for a Fatwa, which is formed based on the information provided by the questioner. Instead, you should refer the case to a legitimate Islamic court for investigation. There may be other heirs who will not be discovered without careful investigation. Moreover, the deceased may have left a will or been liable to debts or other obligations and liabilities which the heirs are not aware of. It is well-known that the settlement of debts and other liabilities are given precedence to the heirs' rights to their shares of the estate. Therefore, you should not divide the estate without referring the case to an Islamic court, if any exists, in order to secure the interests of both the living and the dead.
Allaah Knows best.