Indiana is one of the hardest states to get disability. I filed for SS when I turned 62. I had been getting by prior to that on a seasonal low paying job and a small pension. My story is somewhere on this board posted many years ago.
At the same time I filed for SS I also filed for disability knowing if I got it I would receive full benefits.
In Indiana you have to file and be turned down, appeal and be turned down, then get an attorney and appear before the court.
The judge immediatly told me Indiana recognizes narcolepsy only as epilepsy 😆 but thats how it is in the State of Taxes.
Interestingly I did get disability for the same reason most Baby Boomers do: Arthritis. Like many Baby Boomers I had spent my working life, including the military, on concrete floors. The end diagnosis was I would live the rest of my years in a sendentary state. I think the judge did understand the condition of N and that may have weighed his decision.
All I can suggest is gather all medical references and document, document, document.