Who can appeal Jadhav's military court conviction?

Dawn reports that Indian authorities have transmitted an appeal by Kulbhushan Jadhav's mother. Excerpt:

His mother’s appeal for the appellate court may not be the right way to proceed because under the military’s legal system, the convict has to do it himself and is issued a document for filing appeal at the time of his sentencing.

“It is a violation of the Army Act,” military law expert retired Col Inam-ur-Raheem said, adding that in military the appeal process had to be initiated by the convict, possibly with the help of a counsel.

However, he noted that in the civilian judicial process, appeals could be filed by someone related to the convict. Petitions against decisions by military courts trying civilians accused of terrorism, he recalled, were filed by the parents of the convicts.

It is difficult to understand why Jadhav would not have submitted an appeal of his own -- or why his attorney (if he had one) would not have done so.