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 ʻalayhi wa sallam, is His slave and Messenger.
If the deceased has not left behind heirs other than those mentioned in the question, i.e. no parents or husband for example, then the estate should be divided as follows:
The deceased’s three daughters get two-thirds as a fixed share; Allaah, The Exalted, says (what means): {...But if there are (only) daughters, two or more, for them is two thirds of one's estate...} [Quran 4:11]
The deceased's half-sister from the mother's side has no share in the estate because she is excluded from the inheritance by the existence of the daughters. However, it is recommended for them to give her something of the estate; Allaah, The Exalted, says (what means): {And when (other) relatives and orphans and the needy are present at the (time of) division, then provide for them (something) out of the estate and speak to them words of appropriate kindness.} [Quran 4:8]
The other non-Muslim paternal relatives have no shares in the estate because the Prophet, sallallaahu ʻalayhi wa sallam, said, “The non-Muslim does not inherit from a Muslim.” [Al-Bukhari and Muslim]
Hence, the remaining third of the estate, after giving the daughters their two-thirds, should also be given to the daughters according to the principle of 'radd' (i.e. when the estate is not fully consumed by the sharers of the heirs whose shares have been fixed in the Quran and there are no other eligible heirs, taking into consideration that spouses are not included in the rule of radd). Thus, the daughters get the whole estate as fixed share and by virtue of radd, and no other heir is entitled to inherit.
The estate should be divided into three shares: each daughter gets one share.
Allaah knows best.