My 7 Year Old Has Autism And Non Verbal And

My 7 year old has autism and non verbal and he has suffered with acid reflux for the fist four year of his life he also is allergic to cows milk protein he has had gas that smells of rotting egg his burps too he is not toilet trained but I gave Apple juice to help him pass stool because I figured he was back up but his stool seemed to be normal is there anyth ing I can do for him he dose not seem to be in pain but he is unable to express his self please help