Social Security Disability Insurance program benefits are based on your work history and your diagnosis, and would not be affected by an inheritance. You can refer to the Social Security Administration's What You Must Report to Us section of the What You Need To Know When You Get Social Security Disability Benefits site, and you will see that only income from working would need to be reported. As an experienced claims worker put it in her answer to a very similar question, "The money will not be counted as income, but a resource."

As that expert notes, however, if the inheritance is in the form of property that generates rent income, SSDI benefits might be affected. The inheritance would have to be a great deal larger than the amount you mention to generate that kind of income.

Since the Medicare benefits are tied in to the SSDI program, they also should remain unaffected.

It would be different if you were receiving SSI benefits, which are need based and would be affected by an inheritance. Compare the list of What You Must Report in the Social Secuity Administration's site for SSI and you will see that for SSI inheritance is listed as a form of income.

You can find a comparison of the two programs on this Primer on Government Benefits from the ARC Community Trust of PA.