Psoriasis is often associated with the autoimmune disease rheumatoid arthritis, and the first attack of one or the other is often triggered by stress. It is a big deal, not just annoying skin problems. I hope he can see what's going well with you and be inspired by it, b/c you can't make people do stuff.
You could get him an autoimmune disease test like ANA blood test or anti-gliadin sIgA stool test and see if that scares him straight. Or see if you can get him to do 30 days primal. Just 30 days. Promise him something he likes. The 30 day trial sells a lot of people, b/c they see how bad things get once they're back on the junk.
5'4" 39yo mother to five sweeties & married to their AMAZING DaddyGrok
Current Weight: 175lb__________________________________Goal: 135lb
Deadlift: 240lb________________________________________Back Squat: 165lb
Bench: 130lb__________________________________________Pre ss: 85lb
***Winning a 20-year war against binge eating disorder***