Soups?
I've done potato soup, butternut squash with carrots and sweet potatoes, broccoli.
Baked or fried french fries or oven bake chips.
My allergic to eggs is a picky eater.
I've basically mixed and experimented until I found something and then fed them that all Pesach.
Sweet potato and apple bake.
Find out about nuts. It can be a game changer if he can or can't.
Mine can't so that's rough.