Mom just got Medicaid after paying for a Medicare supplement for years. Do we have to continue to pay for a supplement?

A lot of this will likely depend on what type of services and providers you are likely to use. If the Medicaid recipient is in a NH, then dropping the Medicare secondary policy makes total sense, as all the vendors who work in the NH will take Medicare & Medicaid, so there will be no co-pays needed.

But if you all are still living in the community, then keeping the 2ndary can be a good idea if you are going to see providers who only take Medicare and you will have to private pay for the co-pay which Medicare doesn't pay. Now you still will have to pay for the Medicare "gap" policy, but often there will be a policy that has a zero or nearly zero monthly payment for those who are on Medicaid. Usually these are affiliated with a specific hospital system or group, and you are limited to going to providers within their system to use the free or almost free gap policy.

Perchance, is the gap policy with a federal employee retirement benefit? Like they are with BCBS as their secondary policy in addition to Medicare. If so, the BCBS may get suspended once they are on Medicaid. Medicaid becomes the secondary and the BCBS gets suspended.

We continued to have a supplement; we picked it out each year. But we did not pay for it. Ask your financial case worker how it works in your state.

No, you do not.