I believe a special needs trust is probably the best option available to you. But you really need to consult with an attorney in your state to make sure.
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Agree with Mr. Frederick. The special needs trust is the only safe way to accomplish this. If your parent is already deceased it will take a court order to permit your inheritance to go into a special needs trust without interruption of your SSI / Medicaid benefits. In the alternative, you can accept the inheritance and go off of SSI / Medicaid until the inheritance is spent down.
While your options are limited and a special needs trust could be one of the best available, there are other things that might be done with the money, depending upon how much there is. Certain assets are exempt for SSI/Medicaid purposes. You could purchase a personal residence or a new car for example. You really need to visit with an elder law attorney who does SSI/Medicaid/Special Needs Trust work. You will be glad you did.