Answers
Every applicant, either the investor or his family members, should submit with their residence permit application certified by an insurance agency for the cost of hospitalization and medical care. So your son’s health complications must be checked with the insurance company if it could be included in the coverage that is needed for the certification.
If your son is minor, there are no particular conditions. You need only for the process of Golden Visa annual general health insurance that should be made in Greece of 250,000 euros.
Proof of health insurance coverage that is valid in Greece is needed so check your son's health complications specifically.
He can still be eligible. Like any other family member included in the Golden Visa application, he will need health insurance coverage for Greece, to be concluded prior to the date of his appointment with the immigration agency for providing his fingerprints. The insurance company may require extra premiums to provide coverage, which is something that you will need to discuss with them.
For the time being, there are no health requirements. The only requirement is that all the applicants and family members must have a Greek private insurance health contract.