Is evidence of a Social Security or Veteran Affairs disability decision sufficient to qualify for a student loan disability discharge?

For V.A., yes, if you have been determined to be unemployable due to a service-connected condition.  For Social Security, in some cases yes as of July 1, 2013.  Borrowers receiving Social Security disability benefits in the “medical improvement not expected” category can provide proof of these benefits instead of submitting a certification from a physician.