On basic coverage available - besides the emergency room via getting care in the ER and then not paying the bill (ER's are mostly hand-tied in pursuing people) there's no basic level of care available with no means to pay. And that's really just a back door that can be abused not really "available".
On disability and the like, we do supply Medicare (and Medicaid) to needy folks if they request it and can prove the need for it. Which almost every childhood disability will get proven pretty easily. And depending on the circumstances of the condition only needs review rarely. (7/10/20 years for most, some like blindness never need review)