This reply was originally posted by user Lilies&Orchids in ADDitude’s now-retired community.
You might want to check to see if your son has a co-condition of persistent depressive disorder. I have two people in my household that have depression (one of them also with ADHD) and they complain a LOT. I only recently learned that people with depression can complain a lot. Up until then, I thought depression just mostly meant withdrawl and sadness. For the two in my house, I now see it as an outcome of an overall feeling of discontent and irritability.
The condition is mentioned in this article: https://www.additudemag.com/adhd/article/12189.html.
Medication for depression in my family, as well as other treatments like exercise, being outdoors, a good diet, etc. has lessened the complaining and depression. It is hard to live with a constant complainer. Hang in there and be sure to do things for yourself to keep your spirits up.