He probably has insurance, and since he controls his company's insurance, he probably picked something reasonable. You also need to do that to be competitive at hiring in this space.
It won't literally cost nothing to have a medical emergency, but if you have decent insurance, it's manageable.
The thing about medical insurance in the US is that you really don't know if the policy you have is reasonable for major medical events. Everyday stuff yes, but until that rare major event happens, and you actually try to exercise what you hope you purchased - it's a giant unknown. e.g. The insurance regulators in CA are having trouble trying to stamp out issues where a major medical claim triggers a company review of your initial insurance application to see if there's any way to deny that you even have a valid policy - even if you've been carrying the insurance for years.
It won't literally cost nothing to have a medical emergency, but if you have decent insurance, it's manageable.