Did the mother err in not fully dividing the father's estate (a sum of money and a closed commercial shop) among the heirs (four daughters and a son), and in using part of the money for living expenses, while distributing a small amount equally among the daughters and depriving the son of this distribution? And is the subsequent loss of the money a punishment from God?

There is no sin upon the mother if she divides the inheritance by mutual consent among the adult, mature children, because division by mutual consent and agreement is permissible. It is permissible for an adult, mature heir to waive their right in the inheritance. As for the loss of money and poverty, one should bear it with patience and seek reward from Allah. It is important to note that if the bank is usurious (Riba-based), then saving money in it is a sin, and the money must be withdrawn from it and placed in an Islamic bank or invested in permissible matters.