Is it permissible to accept financial compensation from an insurance company or the National Center for Compensation for work injuries, and is it permissible to dispose of it as one wishes, or do relatives have a right to it, and is it valid to donate a third of the money to whomever one wishes?

It appears that the insurance premiums were paid by the company you worked for, to transfer you to the insurance company upon the occurrence of damage. If that is the case, there is no objection to taking this money, as long as you did not personally subscribe to the insurance company. The injured party has the right to receive compensation for the damage incurred from any party the one who caused the damage referred him to, because he is not responsible for the earnings of others if they are paid to him in exchange for his legitimate entitlement. Based on this, there is no objection to giving this money, or a portion of it, as charity during your lifetime. However, it is not permissible for a bequest of it to exceed one-third after your death, due to the prohibition of the Prophet, peace and blessings be upon him, regarding that. Spending on needy relatives takes precedence over others.