Sure: he's flat out wrong. This has been played out again and again - "winning a war" is meaningless if you can't retain the territory. Unless the world is going to stand by and allow Russia to commit genocide of the entirety of the Ukranian population, this will move from a traditional war to a guerilla war. Ukrainians can fight guerilla warfare longer than Putin is going to be alive and able to maintain support of the Russian population. They couldn't conquer Afghanistan drawing from more than double the population.

https://www.macrotrends.net/countries/AFG/afghanistan/popula...

https://www.statista.com/statistics/1072400/population-us-us...

https://www.macrotrends.net/countries/UKR/ukraine/population

https://www.macrotrends.net/countries/RUS/russia/population