M.H.
I remember when I was younger I could not swallow pills. My mother had to chop them up so I could take them. I had a fear of choking. Maybe your son has a fear of choking because of the way the food feels in his mouth. What ever the case he will let you know when he's ready. Another suggestion is over exagerate how yummy the food is. As you take a bite your son will want to copy you. This may take a little more time. Hope this helps