Is it permissible to continue subscribing to social security, which provides a monthly salary upon reaching the age of sixty or for children after death, knowing that the subscriber has no other income and considers this his sole source of livelihood?

Social Security (ضمان اجتماعي) includes permissible and prohibited aspects, and it is not permissible to voluntarily participate in what is prohibited. As for what occurred in the past and was obligatory, it is permissible to benefit from it to the extent of what was paid. The remainder should be spent on charitable causes or given to the poor according to their needs.