6 year old boy with developmental delay won't eat

My son is 6 years old he was 18 months when he was entered into the Howard County Infant and Toddler program. They have since helped him speak as well as many other behavioral issues. Now we are through the most difficult parts of his issues we have one last one to tackle. My son is still on soy baby formula and stage 2 and 3 Gerber baby food for his main nutrition. The only foods he will eat are goldfish, potato chips, Bacon, Popcorn. He was accepted to the Kennedy Krieger Eating disorders clinic, but health care would not cover it and we could not afford it or receive government assistance. I am at a lost and willing to listen to any advice. He is 6 years old 42lbs. and about 43 inches tall. He is very happy, loving and energetic. Any suggestions would be much appreciated.
Thank you,
LD

[Sally44]

Does your son have sensory issues.  Is he sensitive to light, sound, touch, smell/texture/taste - is his balance and co-ordination okay?
If you think it could be a sensory thing then an Occupational Therapist is the person to see your son.  She may come up with some ideas.
Is there a possibility that your son is on the autistic spectrum and this is tied in with rigid routines as well as sensory issues?
I presume that a specialist has seen him to make sure there are no difficulties such as dyspraxia (ie. muscle control problems related to eating/swallowing).  

[Ldean1]

He currently is seeing an occupational therapist at his school and they are at a lost as well. He is developmental delayed which does fall with in the autism spectrum, but we have addressed sensory issues and that has not helped. He was evaluated at the Kennedy Krieger feeding Clinic for any muscle control problems and that was not the issue. He does eat bacon and popcorn. The only other concern at Kennedy Krieger was food allergies which we tested for and did find a few things to avoid such as nuts of any kind. We are at a complete loss.
Thank you for your thoughts.
Ldean1