I’m so sorry that he is struggling so much. It is so hard to see them so aware of their struggles and not know what to do to help at that moment. 🙁
My son (9) does not respond well to stimulants and he needs a non stimulant and something additional to help his various symptoms of ADHD, so our psych has him on Wellbutrin. It is classified as a anti depressant but has shown to work for ADHD in some cases as well. We have had luck with it.
Best of luck to you both!