He died and left behind a wife, children, brothers and sisters

Praise be to Allah.

If a man dies leaving behind a wife, a son, two daughters, and brothers and sisters, the estate is to be divided as follows: 

The wife gets one-eighth, because there are children, as Allah says (interpretation of the meaning): “their (your wives) share is a fourth if you leave no child; but if you leave a child, they get an eighth of that which you leave” [al-Nisa ‘4:12]. 

The children (the son and two daughters) get the rest, with the male taking the share of two females, because Allah says (interpretation of the meaning): “Allaah commands you as regards your children’s (inheritance): to the male, a portion equal to that of two females” [al-Nisa’ 4:11]. 

The brothers and sisters do not get anything, because they are blocked by the presence of the son, according to the consensus of the scholars. 

When dividing the estate, it should be divided into 32 parts of which the wife gets four, the son gets 14, and each of the daughters get seven. 

And Allah knows best.