@sshah123 , since the SSN is never issued again and her account at the IRS is under her SSN, there is really nothing preventing you from continuing to use the SSN. I do not believe that is the correct thing to do but also do not know of any prohibitions on this. Furthermore , I believe ( for what it is worth ), if she ever comeback to US on a work visa, her SSN would be valid.
If you need more on this consider PM me .
pk
