Quit drinking and smoking. Work out. Sauna. Cryogenic Chamber. Get on Keto Diet. Healthy Carbs. Only drink water. Psoriasis is caused by inflammation. So living healthy and taking anything out of his diet that causes imfammation.
Prob won’t go away unless he stops drinking. Kind of counter productive but I understand. My buddy has psoriasis too but chooses to live with it and enjoy the finer things but he will feel mental and physically better if it tried to live a healthier lifestyle. Anti-inflammation=anti disease(including cancer)