There is an element of truth to what he said, but of course the reality is a lot more complicated. Generally the more low class and common a word is, the more likely it is to derive from Germanic, while the “fancier” a word is the more likely to come from French or some other language. E.G. mother and father derive from Proto-Germanic, while a word like mayor is derived from Latin by way of Old French.

English is still an absolute trainwreck of a language though. It’s a thousand years of just kind of winging it in terms of grammar and vocabulary. It started as essentially a creole and then outlived both the languages it spawned from as well as just absorbing whatever random words and languages it bumped into along the way.

Most other languages at least went through an overhaul or two along the way to clean up their worst eccentricities, but any attempts at “fixing” English over the years have been partial attempts at best and mostly just made things worse. In particular the current state of spelling in English is just the absolute worst with nearly all the rules being utterly arbitrary and just kind of randomly slapped together over the years.