It would be good to read most recent Zone book, TOXIC FAT. It gives the most up to date picture of how the Zone addresses chronic inflammatory diseases.
Here are some addresses to articles about the Zone and Crohn's from drsear.com (Barry Sears' other website): http://www.drsears.com/SearchIndexe...fault.aspx
Good luck to you and your son. BTW, my son is now 24 and he's been in the Zone since he was 9 years old.