Hi Alana,
I had fistuals just like your son. I was put on every sort of medication, until finally went on Remicade. After about the 3rd. Infusion my fistula healed up and thank god has never returned. That was 3 years ago. Im still on Remicade every 8 weeks and I can honestly say I have had no side effects from it. Good luck with your decision, but in my opinion it is worth trying it, and im sure your son would welcome some relief from his fistula.