Son has allergies to nuts & grains except oats. What about oils? Sunflower, Safflower, those also?

   We just found out my son is allergic to all grains, except oats, and all dairy (his Dr. is allowing soy).  Do oils count, such as sunflower or safflower?  Is canola oil derived from corn?  Are all removed enough from the seed/grain and pressed (?) that allergens are removed?  Same with high fructose corn syrup or corn starch, are they ok with corn allergies?  Butter, lactose and caisine (?) removed, is that ok?  Tapioca?  Sorghum?  So many ?'s !

Side note:  Does soy have too much estrogen and not good for boys to eat? Does blood type matter?  I heard that from the local natural grocery store today and it really threw me for a loop!  I'm so confused.