What can a client do if an attorney was retained to file an appeal of an administrative judge to an administrative council and misses the filing date?

My son retained a disability lawyer to file his appeal of an administrative judge's denial of his disability claim to a social security administrative council.. He has been out of work since 2017 due to a brain tumor operation and the loss of sight in his right eye. He also suffers from several complications resulting from his illness. He and his family are living with me and I am trying to pay bills for him and provide them a place to live. Yesterday, the lawyer missed the deadline for filing the appeal (July) even though my son called to check on the status of the appeal filing. He was unable to talk to the attorney directly. Today, the attorney called him and apologized for missing the deadline. He stated that my son could file a grievance with the NC Bar Association or start over with his claim. My question is: Can this case still be given an extended deadline to file by the administrative council under this circumstance? The attorney stat