Ouch, that sounds bad.
I personally use covergirl makeup for nearly all of my stage make-up, with Maybelline mascara. I don't know if it's hypoallergenic, but it's fine to be worn on skin every day. They have foundation, powder, blush, eyeshadow, basically everything. I think I have fairly sensitive skin, but CG is totally fine for me, so it might work for your son. It is also less expensive than buying Ben Nye, or something like that. And, you may even be able to find it in your local drugstore, though I'm not sure if it is sold overseas, so you'd have to check on that.
Hope this helps!