Stop blending his food already!
you already said it that he has molar teeth, he can jolly well chew. of coz having said that, if you r giving him rice, just make it soupy so its easier for him to chew n swallow. cut meat n veggies into small chewable pieces. you have to train him to chew, since he has been eating blended food for soooo long, it will be difficult but you just have to let him learn to chew his food.