Welcome to the forum. I'm sorry to hear of your husband's diagnosis. I'm sure you and your husband have a lot of questions and a lot to learn about Crohn's right now. A diagnosis of Crohn's always comes as a shock. Pretty much everyone here is either the close relative of a Crohn's patient or is an actual Crohn's patient (like me), so we've all been down the path you are now starting. You will find a lot of knowledge and support here.
I respect your husband's decision to try a more natural approach.. It's perfectly understandable. For the first five years after my diagnosis I allowed only mild medications - no biologics. My disease was "mild" so why bring out the heavy artillery? And my disease stayed mild until it didn't. It suddenly turned a lot worse and I developed serious extra-intestinal manifestations. I've been on Stelara ever since, and so far the Stelara has kept me in a good remission with no side effects.
Hopefully your husband's disease will not worsen and will respond well the natural approach, but you should be alert and open-minded to the possibility, in fact fair probability, that it won't. In which case he may well need to embrace the biologics before things get too bad. The reason why is that the damage to the gut that Crohn's inflicts is cumulative. You body works like crazy to heal the the Crohn's ulcers, but as the damage continues for year after year the scars and inflammation builds up, fistulas develop, and the patients is left with a nonfunctional length of bowel that is shredded almost beyond recognition. At that point the only alternative is surgery to remove that lost-cause length of bowel.
Keeping your husband's disease in check enough to avoid surgery and enabling him to live a mostly normal life should be the top priority. And so far the biologic drugs have proven to be the best and most powerful medicines to achieve this. So if the natural approach works out for him, great. But if it's not working very well, don't delay the switch to biologics for too long. You don't want to end up living with a bunch of permanent damage that was avoidable.
Good luck! .