I think the link he shows between supporting Trump and favouring authoritarianism is tenuous but I can't spot any obvious flow in the main thesis - most Trump supporters are doing well economically but feel alienated culture-wise. Also, important to note but not pointed out by the author is that the support for Brexit was highest in areas that had seen a large percentage change (1% -> 2%) in immigrant population, not necessarily a large change (10% -> 14%).