Will the remaining children have a share in the money that the General Organization for Social Insurance will disburse to only two of the deceased's children?

The beneficiary of social security for the deceased cannot be determined without knowing the reason for their entitlement to it. If the social security was in exchange for money paid by the deceased, then it belongs to all heirs and is distributed among them according to Islamic law. However, if it was a grant from the issuing entity to some of the deceased's dependents, then it goes to those specified by that entity, such as his wife or unemployed children.