8 year old who can't stand food with texture - help!?

My friend has an 8 year old who has never been able to eat textured food, like mashed potatoes, pudding, nachos, all sorts of things. He basically lives on chicken nuggets, corn, and hot dogs, that sort of thing. He threw up a lot as a baby, and has a very sensitive stomach. He actually throws up if a food is not bland and tasteless. His mom thinks it could be a learned response (in his head), but with a basis in a real problem with food and his reflux issue. She has tried forcing him to eat certain foods, but he throws it up. If his nose is runny, it will cause him to get nauseated and throw up. She is at her wit's end to get him to eat other foods. Any ideas?