I wish I knew more about this, but my loved one has Medicare and Medicaid. She does have a medication supplemental policy though. If they have Medicaid, I don't think they need one, but perhaps someone who is familiar with it will respond.
Is the person 65 or older? Is the NH in the state they now reside in? If already on Medicare why wasn't a supplimental chosen to help with the , 20% Medicare doesn't pay and perscriptions? If going into a NH you continue with whatever you have in place. Medicaid comes in for medical according to ur income or disability. Medicaid will pay for the cost of the home if you have no assets and income is low.
Are they on medicaid or just medicare? If just has medicare she can get a policy during open enrollment. Because of the Affordable Care Act aka Obamacare prexisting conditions cannot disqualify someone for coverage. If they are on medicaid already then no need for sup policy.
This article may help. Also, open enrollment for insurance starts Oct or Nov and ends b/f the first first of the year.