Have a client who is a former lifetime fireman who is retired and collects his pension.  He came down with cancer and informs me that firefighters with cancer do not have to pay tax in RI and the fed due to having been diagnosed with cancer.  His 1099R has code '7' for normal distribution but he presents a document from the RI municipality that his retirement was changed to a status of "disabling occupational cancer" on or about February of 2022.  My question is what is the federal and state implication of this determination?

As always, thanks for your help in advance.

Patrick D.