Ref. No. 1876/43-1737
In the name of Allah the most Gracious the most Merciful
The answer to your question is as follows:
If the legal heirs are only one son and four daughters, then the entire property left by mother shall be divided into six shares, out of which two shares shall go to the son, and each daughter will get one share. The son gets double share and daughter gets single share.
للذکر مثل حظ الانثیین (سورۃ النساء)
And Allah knows best
Darul Ifta
Darul Uloom Waqf Deoband