After your SWH; I see that your son has been evaluated and receiving help with speech. This tells me that it's likely his mouth and muscles are a part of the reason he acts this way. May be a big part. I urge you to talk with his speech therapist about occupational or feeding therapy.
My grandson still stuffs his mouth. We've been told he isn't able to "feel"the food unless his mouth is stuffed. My grandson also eats so fast he vomits. All a part of sensory issues. He often responds to coaching. "Slow down. Take a break from eating. Swallow what's in your mouth now. Take one bite of this and then you can have that. When you eat half,.you can hAve dessert. The understanding is, if he makes an effort he gets dessert. Same expectation for all the kids (ages 5 and 3), one bite becomes two, becomes three over weeks or even months. His parents praise their effort. The 5 yo was just diagnosed with autism. She is a very picky eater. In fact, she eats so little, I'm spruced her weight and height is within the normal range.
My daughter was advised to make eating about effort while giving very little attention to actually eating.
My grandson did those things. He was diagnosed as autistic as well as having developmental delays. I don't know if your son is autistic. I suggest he be tested for disabilities that will hinder success in school.
Fixation on one thing and stuffing his mouth with too much food are symptoms of autism. Throwing his vitamins, refusing to co-operate with you. If he acts angry and aggressive, has frequently tantrums, can also be symptoms.
Federal law requires school districts test and treat, if that is needed, for any disability that will make learning difficult. This service is available from birth. It 's part of "No Child Left Behind" legislation. The title of the office that provides this service for my grandchildren is Multnomah County Special Education District.
They will first do a phone.interview to determine if your child may be eligible for an evaluation. If so, they start gathering information from others.
I suggest you call and make an appointment. It is possible that he is fine. If he needs services, they'll talk with you about the services they will.provide.
You can also have a pediatric doctor what he thinks. You can find one at a teaching hospital. My 5 yo granddaughter was just evaluated at the state teaching hospital. She was evaluated by the district and then referred to the hosoital clinic. She is autistic. Her mom and dad attended an IEP meeting today to discuss what she needs and how the district can help her. IEP stands for Individual Education Plan. My grandson was diagnosed and began treatment a couple of months before he was three. He continues with an IEP at 12.