I had two massive rectal fistulas in 2007 when I was diagnosed with CD in the colon. GI wanted to turn off my immune system with remicade saying nothing else will heal fistulas as large as I had.
I decided against remicade. After some research, I went on the SCD diet. I followed the diet with fanatical dedication and in 7 months both fistulas were completely healed, and all my other symptoms of CD like white mucus and blood in the BMs were gone. That was in 2007, and to this day, I have not had a single flare or a fistula or any other problem from my CD, and I still follow the scd diet, but not as fanatical as before. The only drug I ever took was pentassa which I am still taking.
I suggest reading the book "breaking the vicious cycle" you have nothing to loose and all to gain.