My son was just approved for chapter 35 benefits. He has been 18 since Sept 2016, but is still in high school. Graduating on June 9. His approval date is Sept 2016, even though it was just approved. Will he receive any back payments? And I know my dependent compensation for him stops when he graduates, if he is using Chapter 35. Since they are dating it back to Sept, will I have to pay back any dependent pay received for him from Sept until now?