Thank you for writing and I'm very sorry your son has no health insurance - this is a national disgrace. Everyone should have the right to health care.
Is your son eligible for Medicaid? If he is, he needs to apply asap.
If not, google free clinics and hospitals near you - they may be able to help. If things get very bad - present him at a County hospital - they cannot turn him away for lack of funds. They may help him free of charge or put him on a long-term, realistic payment plan.
Please keep us posted.