Food allergies

Hello beautiful people, is there anybody who have children in their family that’s allergic to wheat, eggs, or peanuts. What are some alternatives you give your children? My nephew is allergic to those items and my sister is a bit flustered cause all the food/snacks my nephew eat he’s allergic to it. I’m want to lighten the load for her and exercise all of our resources ( this app, google, doctors, YouTube) in helping her make some kind of list of foods she can try with him. Thanks!