Is an employee sinful for benefiting from the health insurance provided by the company for its employees and their families, knowing that it is mandatory and not optional?

If the health insurance is based on mutual solidarity (takaful), then there is no problem in benefiting from it. However, if it is commercial, the employee is permitted to benefit from it, and the sin falls upon the insurance company, not on the employee. This is unless the company mandated it and could not find cooperative insurance, in which case there is no sin.