I Have A 5 Year Old Grandson Who Is Having

I have a 5 year old grandson who is having difficulty defacating correctly. He has been to the doctor several times, and the doctors are not getting the full story about his diet. They are being told that he is eating a healthy diet, and this is a blatant lie. He is being given nothing but processed foods and NO vegetables (either fresh or frozen). The only form of fruit he receives is juice (mostly apple). He eats candy , chips, donuts, etc. and I suspect this is the reason that there is very little stool being formed. The doctors are treating this as constipation, giving him several different laxatives and suppositories. None of these work. Also, his mother has not taken the time to offer toilet training, and she is encouraging him to stand behind a chair in a pull-up and try to have a BM rather than taking him to the toilet. I am very concerned and have been for a long time now. I can no longer "Look the other way!"