Glad your son is doing better, MrCuddly. I've gotten into dosing vitamin C to bowel tolerance and have learned a lot about how effective it is for just about any condition--Dr. Thomas Levy calls it "the primal panacea" (when enough is taken). This article confirms its importance in Crohn's: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2425408/
It's a lot cheaper than those Crohn's meds!
Of course, he could take it along with his MJ use.
btw, I found a flax/hemp oil I really like. It's from Spectrum and they call it "Savory Blend." Cold-pressed organic flax oil, cold-pressed hemp oil, natural garlic flavor, organic rosemary extract, mixed tocopherols vitamin E, oil of oregano. I use it on salads, in dips etc. Haven't tried swishing with it--don't want garlic