I have a two year old son and he is starting to concern me he still wont form complete phrases, and he bites his thumbs when he is angry, excited, sad or scared. He does not follow comands can there be something terribly wrong with him. Could it be a syndrome of some sort?

Don't worry to much, as he is child and even can't speak properly then what will he do, definitely he will do something to express his feeling, so he is biting his thumbs to do that. For ex, When a child feels hungry, normally he used to cry, so his mama can recognize that he is hungry. Most of the infants has some kinds of tactics to express his feeling, it's your responsibility to understand.