In the majority of states, you may be eligible to purchase small employer group coverage as long as your adult child is a full-time employee. You can purchase small group coverage with the help of an agent, broker, or directly with a health insurer who provides small group coverage. Check with your state Department of Insurance to see if this applies to you. (45 C.F.R. § 144.103).
On Private Health Insurance Coverage & The Health Insurance Marketplace