My son is using a magnesium supplement called Natural Calm and it’s helping (in addition to melatonin). He also sleeps under a weighted blanket.
Melatonin only helps with falling asleep, not staying asleep.
Some kids are prescribed Clonidine at bedtime to help with sleep. You are right, he can’t function well if he’s not getting adequate and restful sleep. It only makes ADHD symptoms worse.
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism