For a natural couch potato like me, it sounds disingenuous to recommend exercise, but here it is: get you and get your son some exercise. Not the team sport variety, but the individual kind like swimming, running, tennis, etc. You’re looking for highly aerobic, highly sensory (for some kids) and with sustained intensity. In other words, get him and his senses tired and saturated. We picked swimming for my daughter, running for my son, hockey turned to biking for my husband. I run / walk/run when I can. Coming home, snacks. We have an expression: “Hangry”, meaning hungry and angry. Whenever someone walks in the door after school / work, hand them a cheese stick. Don’t try to argue with a mentally wiped out, physically underexercised preteen: feed them and send them to walk on an errand.
Managing wakeup time is also a key in our home. Sleeping late makes my 12 yo girl a cranky child for the remaining of the daylight on the day! Sleeping in means sugar low means sleeping even later, meaning even low blood sugar, and when she wakes up she’s a dragon. Nothing gets done, friends are called with haphazard requests for plans together, homework does not get touched, little brothers are tweaked moms (moi!) are told off. organizing Friday night so that she can wake up at a reasonable time on Saturday morning is a must, if we are ever going to deal with each other in any kind of civilized way. Beside all the other great recommendations that you have, here’s mine: look at sleep patterns and feed yourself and your sun at the right time.