I have a little friend w autism that had to proble as well. The OT thought it was sensory and used the tooth brush. The behaviorist thought it was attention seeking and put a plan together w the school. Ultimately a couple of years later the mother tried a gf-cf diet and it was gone in less than a month. He can now (like my on) tolerate dairy. And you may not notice if thereisb minor gluten insult. But if he goes back to eating gluten or dairy regularly the refux comes back.

He might not feel his mouth and tongue very well so he might not realize how much he is eating and regurgitates it as a reflex. My son use to do this a lot. We did exercises to "wake up" his senses in his mouth. We used a vibrating toothbrush to help and we made him drink thick liquids out of a straw (like a malted shake or apple sauce) this has really helped his senses. Good Luck!

While it could be anything, autisim seems to come with "acessories" very common to have allergies, stomach problems ect. My bet is he swallows the food, then cant swallow and must finish chewing. Since they look to NT family members, he might be trying to chew/consume his meal at the pace of other family members. Try making a point to chew your food more slowly in his presence. You dont need to talk to him about it, just do & see if it helps. Another issue is he is half swallowing to check if hes done chewing.

My son tends to swallow his food before chewing, which sometimes causes meal-time vomiting. Also, there are certain times when he can't control the errant coughing fit, so he ends up throwing up by accident.

I've never heard of that before... Is it a sensory issue? Try processing the food in a blender and see if he does the same thing. He might jut like the texture better