My Dad's Disability Funds are stopped as of Aug. What should we do?

My Dad had a stroke 2 yrs ago in June. He had a Govt. job. He was forced to retire early that next Mar. because he couldn't perform his job anymore. Now we just found out his disability runs out at the end of Aug. because the state doc (the one they hired not us) says he is able to work. He isn't. He can barely walk even 2 yrs later. My parents are so upset. They really don't know what to do now. They own their home but their medical bills are outragous. Does anyone know of any steps to take next. I want to help them without having to move in with them or move them in with me and they lose their privacy. My Dad is only 56 yrs old. Any advice/help would be greatly appreciated.