It really depends how many eggs he consumes on a regular basis. You can develop an allergy to eggs due to overconsumption. I recommend rotating them out for awhile and then re-introducing them in small increments depending on how it makes him feel. Also, what is he cooking the eggs in? If it is butter he could have dairy intolerances that are making him feel that way. But yes, overconsumption of eggs especially if you are eating them on a regular basis can get you into trouble.
"If man made it, don't eat it" - Jack Lallane
People say I am on a "crazy" diet. What is so crazy about eating veggies, fruits, seafood and organ meats? Just because I don't eat whole wheat and processed food doesn't make my diet "crazy". Maybe everyone else with a SAD are the "crazy" ones for putting that junk in their system.