Crohns Disease - Stomache (complications?) and 6mp

My son will be on 6mp once again - as the disease continues to reside in his stomache and now the colon (buttox has lots of inflammation). We worry about future surgery and it turning into anything worse, can surgery be successful in he stomache. What will it entail and or the possible negatives of having it in the stomache verses the intestines. Is anyone experiencd in the this area......the disease typically sits in the intestines with most. I am nervous about this. Thank you kindly......!!! LUV4MYCHILD