I don't think you want to use it as there are some that say it's a lifetime egg withdrawal. I think the Permethrin or garden dust labeled with Permethrin would be a better idea.
It might be the mites caused anemia. What you're doing is good to replenish his vitamins. I'd get him some probiotics too. Sugarfree Greek yogurt, or powders like HydroHen for the water.
If you see any more mites or signs of them, I'd get some Permethrin powder and dust him and the coop...