You will have to work on the diet, you know, but my own kid that was among the most pickiest I have known of, became much better also with his food issues after iodine.
Check out Weston Price`s recommentations for kids (and adults) http://www.westonaprice.org/childrens-health
One have to start somewhere; I often start with finding one kind of fruit-juice they like. In there I can put iodine, boron, vit b powder, vit c powder, magnesium glycinate. Your jummy bears are to low in B and C. I checked the ingredients, ok, but in general I avoid such unless it is the only the parents can get into the kids of supplements)
Iodine can be put in milk too, no taste of it!
Liquid varietes for kids are possible, but they are usually quite expensive.
I would start with a one, then two drops of Lugols, or purchase some SSKI from Trapper.
I would drop the Calcium, especially if he drink milk or eat cheese. Magnesium works better without the calc.
Magnesium is super, kids are frequently very low, especially the picky ones; purchase a powder that is palatable, as glycinate or malate. It can be sprinkled in food or in drinks. Chocolate craving can be a magnesium deficiency.
Selenium methionine is a must in Iodine supp; 50-100 mcg, can be sprinkled over his dinner.
Boron; 3-6 mg, will counteract some of the fluoride damage.
vit C; 150 mg x 3 times a day.
Vit B (all of them) 100 % of RDA at least.
High omega 6 intake (from cereals, grain, fast food) may cause dermatitis / skin inflammation. Helped by sweeteners, food coloring . Start by reading ingredients, observe if he reacts to some food or sweets. Coconut oil is great for skin BTW!
The more saturated real fat he gets, the less omega 3 you will have to give.
Focus more; the brain needs saturated fatty acids! Iodine!! Boron,zinc magnesium (calming)
Slowly get him on less Sugar / grains.
No artificial sweeteners at all.
NOW food has good supplements; I like several of them. They have some zinc loosenges, chewable that I believe would help his dermatitis. They have powders like magnesium ascorbate (for his vit c)
Other from that I dont know many Brands over there, as I live in Norway.