I understand. I have some pretty picky eaters myself, and I got really worried when my two year old was still on mac and cheese baby food, and would eat nothing else.
Something that you can try is just leaving food out within his reach, that is healthy and likable. I found that when my kids are little, they would rather toddle around and eat than sit down at the table. None of them have disorders: this is just a normal thing for kids.
You never know what he might like to explore in food. If he is hungry, he will eat. If he is in control of the situation, and doesn't feel pressured by a setting where you are around, then he might be more open to eating what he himself "chooses." Place a few completely new choices of food where he can pick things out on his own that are tasty yet healthy.