My son's health insurance through work is very poor. Is he eligible for any supplemental type of insurance?

We live in Wisconsin and there is Badger Care. This apparently is not available if he has health insurance offered through work. The maximum this policy will pay is $2000. What happens if he has a major illness or accident requiring hospitalization?
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health-quotes.talk4fun.net - here is my health insurance plan. As I remember they can provide such a service.
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