Hi, not sure what you mean by the term "leaky gut" but I certainly know what fistulas are. I had several anal fistulas operated on over 2 years ago as antibiotics weren't working. My first couple of procedures involved fitting setons, this is where they lay the fistula track open in the hope that it will heal. I had a couple of these same procedures and none of them worked. The only thing that totally healed the fistulas for me was to have a stoma fitted so I could rest my rectum. After 11 months they were totally healed but I didn't have the stoma removed until 13 months after that. I didn't expect to feel so well after the surgery had settled so I was in no rush to reverse. Hope this helps a little. Hopefully your son can find the best procedure for him and they will heal totally.
Ruth