Here's an interesting blurb on fungi and Crohn's.
https://asm.org/articles/2021/july/broadening-the-microbiome-fungi-in-inflammatory-bo
My understanding of the article:
1) IBD is a complex illness. There are up to 240 different genes and multiple environmental risk factors. Scientists haven't hashed it all out yet, but seems to be miscommunication between immune system and microbiome.
2) Fungi are a relatively difficult part of the microbiome to study compared to bacteria. Our knowledge of them is much too small. Some types are helpful and some harmful.
Debaryomyces hansenii is an especially bad guy! This shows up especially in meat and cheese. Large amounts of meat in diet are associated with Crohn's relapses.
And here's another that mentions candida specifically:
https://news.weill.cornell.edu/news/2021/11/antibodies-help-keep-harmful-forms-of-gut-fungi-in-check
1)
Some (not all!) patients with Crohn's have C. albicans in gut and antibodies to yeast in blood. These antibodies don't seem to be in the gut where they belong. Healthy people sometimes have C. albicans in their guts too.
2) Scientists propose giving antifungal antibodies (no mention of anti fungal drugs) to patients with this particular problem.
Here I am editorializing again, but it strikes me as very unlikely that a patient with Crohns' would have the lab results your doc states, namely yeast in blood and urine but not stool. The Crohn's patients that do have candida growths have them in the GI (or intrabdominally), not urine and blood (as far as I can tell after googling for half an hour). Yeast infections often shows up in the mouth for Crohn's people. You know lots more about Crohn's than I do.
Urine yeast infections are far more common in women than men, like other bladder infections. Men get these types of infections after using a catheter or having surgery to the area. Yes, they can happen with immune compromise, so if your son it that immune compromised with the Crohn's your Crohn's doc would know and be involved in treatment? I think?