I can only speak from my personal experience. If he already has inflammation (any way to quantify/qualify?) and "stricture", that is hard to assess the situation. All I can say is that I distrust both the allopathic and naturopathic sides of the wellness equation. However, naturopathic diets/supplements can be more effective, in my biased opinion, in the long run. This can be slightly (depending on the individual) tedious, though. If your son has a mature and vigilant outlook on the matter, I think it is the way to go.
After a surprise 10cm, or so, resection and appendectomy 10 years ago (no resections/hospitalization other than check ups and joint pain once, to no avail, since), I kind of aired on the side of caution for over a year, taking azathioprine and pentasa--to no discernible benefit. From there, I tried going on a whole food-ish diet. Eliminating all preservatives and gmos and sugars (synthetic or otherwise, except stevia/honey/and cane sparingly if at all) and transfats. Just eating real, whole foods is a shift from most people's lifestyles ($/time/culinary skills). I have mostly relied on alternating quality probiotics (two different kinds a week--meaning one kind every other day, like once or twice a day-- is probably good, usually on empty stomach before bed and in morning for a while before eating) and 3 grams of enteric coated actual omega 3 fish oil daily (like, say, NOW ultra omega) and 5,000 iu vitamin D3 daily and occasionally sublingual B12 (methycobalamin) and 2 caps of Black Cumin Seed oil from Life Extension brand per morning daily well before food. Other than that, I've taken LDN as a precautionary measure (cost/benefit analysis seems alright in my opinion) for the past few years. I have not drank tap water, other than a few times per year--literally--for the past 8 years. I've always relied on reverse osmosis or a combination of table top filters for my --literally--100+ ounces of water a day, not including juices, etc..
From there, I can only recommend eating only foods that he can tolerate. That is, eating whatever allows him to be asymptomatic (no diarrhea, cramps, joint pain, whatever) most of the time. Sometimes this may be going on stretches where only a few foods can be consumed, one at a time, until restoring the digestive system to a more healthy stasis (anti-inflammatory/probiotics/prebiotics/antioxidants). There is no clear cut path to tread down this route. Any honest person would tell you the same for the allopathic route which is also based on symptom management--though, while completely denying and ignoring any dietary factors on individual symptoms.
My largest complaint with doctors is their lack of inquiry and scientific proof. I mean, some may take whatever blood tests/calprotectin/scopes/pill camera once ever and determine a lifetime of "treatment" from there, without really ever demonstrably verifying the midterm/longterm effects of whatever battery of pharmaceutical potions poured into you, from diagnosis to the 5 or 10 year mark. That is unless you have problems, then they just cut you up and place you back on the same or similar drugs. There is a limit to this method. Some of these drugs have very serious side effects and may cost thousands of dollars a month.
For some the takeaway may be to try these things in conjunction with pharmaceuticals. I do not know what will work for most people, it is largely an individual cast of symptoms/intolerances/triggers/locus of inflammation which requires a whole lifestyle shift. If you feel like reading a somewhat coherent thread on my outlook, having almost 10 years of experience with this dis-ease, ferret out my thread in the "Success Stories" section of the site titled "MY Supps for MY Dis-Ease". Best of luck.
