This section applies to: each individual health insurance policy that: provides coverage on an expense–incurred basis; and provides coverage for a family member of the insured; each group health insurance policy that: provides coverage on an expense–incurred basis for employees of an employer or employers or members of a union or unions; and provides coverage for a family member of a covered employee or member; each individual service or indemnity contract that: is issued by a nonprofit health service plan; and provides coverage for a family member of the subscriber; each individual contract that: is issued by a health maintenance organization; and provides coverage for a family member of the subscriber; and each group contract that: is issued by a health maintenance organization; provides coverage for employees of an employer or employers or members of a union or unions; and provides coverage for a family member of the covered employee or member. Each policy or contract subject to this section shall provide that the same health insurance benefits and eligibility guidelines that apply to any covered dependent are available, on request of the insured, subscriber, employee, or member, to a grandchild who: is unmarried; is in the court–ordered custody of the insured, subscriber, employee, or member; resides with the insured, subscriber, employee, or member; is the dependent of the insured, subscriber, employee, or member; and has not attained the limiting age under the terms of the policy or contract. On request, an insurer that issues an individual or group health insurance policy that provides coverage on an expense–incurred basis, a nonprofit health service plan, or a health maintenance organization shall offer family members’ coverage to an insured or subscriber regardless of the marital status of the insured or subscriber. An insurer, nonprofit health service plan, or health maintenance organization may require proof that the insured or subscriber is the grandparent of the grandchild. If the insurer, nonprofit health service plan, or health maintenance organization requires proof under this subsection, the insurer, nonprofit health service plan, or health maintenance organization shall pay the cost of the proof.