@sbpilates
I'm sure you can get an extension from the court for cause.
As I said, you are still in the information gathering phase. Did he inherit cash from his parents? Or securities? If cash, what did he invest in that had a gain in 2021 when everything else was going down? Where is the 1099 from the broker in 2021? Why assume he had 10 years of missed tax returns if, in most of those years, his only income was social security.
Gather your information and try not to worry so much.
