Crohns is a disease characterized by inflammation in the digestive tract.Inflammation in the digestive tract causes a wide range of symptoms -- D, ulcers, malabsoprption, bleeding, structures, fistulas, etc. All of the commonly prescribed medications for |Crohns are designed, through one mechanism or another, to reduce or eliminate that inflammation, thus reducing or eliminating the symptoms and damage. So of course it is possible to avoid meds -- you will simply have more and more continuous inflammation, of only at the microscopic level. That's like asking if you can avoid aspirin or tylenol for a headache. Sure you can, but you will still hjave a headache.
You won't die of the headache, and you probbly won't die from the unmedicated Crohns, but th chances are very strong that you will suffer a lot more discomfort from either withoutmeds.