Sorry to hear that, my heart goes out to him. I post a lot about it here on HN, you can scroll through my prior posts, about half are on this. Also feel free to email me. Chrons is pretty common in people with hEDS, which is what I have, so while I don't have direct experience with having it myself I do know quite a few people who have had it.
Edit: had to do a quick double check, but the foods that I eat, and don't eat, are specifically for hEDS/ME/CFS brain fog which I believe is IL-1B cytokine related and I think it's plausible that this probably has a crossover to Crohn's. Listing it here as something to consider; A diet of zero sugar and zero fruit, a lot of kale, chia seeds, and pumpkin seeds. I do one meal a day, and an occasional extended water fast. For vitamins I take TUDCA, DIM, and D3.
Prolonged use of steroids can cause dysautonomia which causes a plethora of other issues. So understanding dysautonomia could help. I also use a weak ligand approach to dysautonomia which is unusual with the use of modafinil and amitriptyline.
Low Dose Naltrexone (LDN) is a rather benign medication that's been known to help. There is little downside to trying it - so it can be used as a bit of a diagnostic in addition to treatment. Of course DIY research rules apply.
One of my more out there theories that seems to be quickly gaining traction is that a low dose of GLP-1 agonists can be surprisingly good for autoimmune conditions.
Most of my other peptides are hEDS focused and include VIP, Ipamorelin, Selank/Semax, and BPc157/TB500. Though I really only take the ipamorelin and semaglutide these days. These are a bit more risky but since my alternative is to be very sick I have a different risk tolerance profile compared to most.