Is Kindergarten required where you are at? What happens if you pick him up at lunch time, feed him at home, give him a nap and do some after schooling as needed? IMO flipping a K classroom is a not an easy ask.
Where I am, children who still need to sleep (perhaps that best medicine!) are kept back... you find wide range of ages and abilities come K (this creates its own issues of course).
Regarding the iron, what I have found that works best is ‘Floradix'. The gluten free variety has the most iron per serve. I split the dose between two servings. Dairy has a big impact on absorption of iron. You should avoid serving milk (and apple juice!) within an hour or so of giving the Floradix. The vitamin B will also help with energy. Of course, discuss this all with your own doctor!!! For my DS11 we treated him with Floradix only, his levels were even worse that your DS’s at the time. You can buy it online at iherb.com for example, or at Wholefoods, etc. You can also take it yourself :-)
Certain dried fruit, e.g. raisins are a good source of iron as well pumpkin seeds -- keep these in mind for snack time.
I bet your little guy is super tired and uncooperative as a result of his iron counts, not to mention his age and activity levels. I don't have personal experience with ADHD but wonder how greatly his symptoms are impacted by the anaemia???
