He didn't. Most of the stuff Trumpers say about DeSantis are flat-out lies.
It's all they've got.
https://www.newsweek.com/fox-news-calls-out-ron-desantis-flip-flop-ukraine-1790380
He continued: "The other thing is, as you become a national candidate, you have to have the talking points of a national candidate. We want to support the Ukrainian people, we want to make sure we're doing the right thing, and we can't just stand by while Russia sort of gobbles up bits and pieces of Europe. That's what he's trying to say now, but before I think he was sort of playing to the crowd a little bit."