Note that the word “previous” is preceded by the word “the” so it means the 5 years just prior to the sale. The word is not preceded by the word “any”
Further, the argument about the sale being precipitated by illness/ disability is based on the “use” AND “residence” by the owner (your son) , which is one of the reasons I raised the clarification of who actually owned this property....if he had lived with you all these years then that would have been different
Lastly, as you can have only one primary residence, how could he have purchased a home with his spouse and lived with her and THAT not be his primary residence?
Sorry, but suggest your son sit down with a CPA and straighten this out
