A.B.
My daughter was a withholder who also was on Miralax every day for a year. The doctors wanted us to do enemas to make her go, but I thought it would just scare her even more. Her bowls would "leak" a lot which was actually the laxative causing bm to drain around a larger bm. We did not know what to do anymore---we tried everything from rewards to getting mad at her. My first question for you is does he eat a lot of cheese or cheesie things and drink milk? My daughter was addicted to milk and anything w/cheese. We have a friend who suggested that we take her off of dairy and try goats milk. Cows milk has a protein in it that is hard for little ones to digest and goats milk is much easier on the tummy.
She's been off of dairy for about eight months and she's doing great!!! We don't specifically read labels for dairy, but we don't give her things made specifically out of dairy. We've also taken her off of cheese crackers. Another snack to avoid is gummie snacks---they are very binding. Peanut butter should also be limited...it's pretty constipating. We still give her some peanut butter, but we also give her almond butter. A great snack for him could also be pecans and grapes---pecans are very high in fiber.
I don't know if this will help, but it has made my family's life better. She may not go everyday like the dr's wanted her too, but she goes every two to three days (which is better than every 7 to 10!) and no more leaking!!! Good luck!