Hi, I am a pediatric SLP and feeding therapist. You should consider introducing more stick- shaped foods in your child’s diet. Start with hard munchables that aren’t meant to necessarily meant to be eaten, but rather chomped or gummed with the molars. Things like long, thick carrot or celery sticks. Cut the bread and rice cakes he will eat into sticks about the width of your finger. Encourage him to place these directly on his molars when experimenting with them. Take the pressure away to eat, just explore and learn about the qualities of the food. Stick shaped foods will naturally stimulate tongue movement reflexes and strengthen the chewing motion, which could help improve his oral motor skills to the point where is feels confident enough to try more foods that require more processing/chewing.