autistic teen refuses to swallow foods and even his own spit

[Peach0327]

My 16 year old moderately autistic son stopped swallowing all and any kinds of foods as well as his own saliva.
After a double round of a stomach flu I am assuming he scared himself into not wanting to swallow anything for the fear of it coming back up. This landed us at the hospital for dehydration , for tests like endoscopy, swallow studies aso and now he is on a feeding tube. We went from a normal eating kid (picky, but I d KILL for picky at this point) to a kid who needs round the clock feedings and is hooked up to a pump all night, just to keep up with his calorie needs at 5 foot 10, 200 pounds. We started him back on anxiety meds, and are working with our speech therapist to start feeding therapy. I m not sure how successful this will be with a tube down his throat. Since they placed the tube, he stopped talking altogether, we are able to draw one or two words out of him which sound like he is gagging . Does anyone have experience with something like this? ,