Praise be to Allah.
If a woman dies and leaves behind two daughters, a sister and a nephew (brother’s son), the estate is to be divided as follows:
The two daughters get two-thirds, each one getting one third, because Allah, may He be exalted, says (interpretation of the meaning): “if (there are) only daughters, two or more, their share is two thirds of the inheritance” [an-Nisa’ 4:11].
The sister gets the remainder of the inheritance on the basis that she is a relative through the father.
The nephew (brother’s son) does not get anything.
Shaykh ‘Abd ar-Rahmaan as-Sa‘di said: If there is anything left after the daughters have taken their share, it should be given to the sisters, and they should not be overlooked in favour of relatives on the father’s side who are more distantly related than them, such as a nephew (brother’s son) or paternal uncle.
End quote from Tafseer as-Sa‘di, 1/170
And Allah knows best.