Social Security Questions? Ask a Social Security Expert
You need to contact Social Security Administration as to the status of your grandson's benefits. It is strange for you to receive notice from the State (Medicaid), but not also from the federal government. SSI has both federal and state components. The state component cannot be stopped or suspended while he is still receiving the federal component.
You need to contact both Social Security Administration and your state's Medicaid's office as to the status of his benefits.